Brother Swindled Up To £100000+ Out Of Mother With Dementia

I lost my mum six months ago to complications from Dementia, which she was first diagnosed with in 2012. This story has its roots even further back than that. The story starts in 2008. My dad was on a life support machine after contracting an infection while on holiday in Wales. He was going through chemotherapy and caught a bug which nearly finished him off. We hired a caravan local to the hospital and my brother stayed at the family home due to work commitments. I popped back every few days to wash clothes and get fresh ones. One day I came in to my parents house to find my brother showering and there were new clothes strewn across the dining room table. My dad's debit card was on the table wrapped in receipts for nearly £500. When he got out of the shower I confronted him. He exploded in a fit of faux righteous indignation. He couldn't grasp that it was wrong to spend your dad's money while he was on life support. My dad pulled through and the elation of having my dad back sort of overtook the disgust at my brother's actions, plus my dad was usually on top of his finances and I assumed he would deal with it himself in good time. Fast forward to 2014 and my dad succumbed to sepsis. My brother was living with my mum and dad, and was quite close to her. She listened to him, and couldn't see anything wrong with him. At some point between 2012 and 2016 my mum lost any ability to deal with finances, she just couldn't get her head around it anymore. My brother took over the running of her finances, and despite me voicing my concerns to my sister, she assured me she trusted him. Several times over the next few years I tried to convince my sister we should get power of attorney and have mum's finances dealt with properly, but she insisted everything was in hand. He moved out of her house in 2019 and I moved in, but was convinced by my brother and sister to leave the finances the way they were. My mum deteriorated in early 2022 and became incontinent both ways. I stayed with her and postponed going back to work to look after her. My mum and I had some heart to hearts in those precious moments when a dementia patient is lucid. I apologised for being a little turd growing up, and she apologised for being too harsh with discipline. It was at this point my mum apologised to me and said she didn't think there was any money to leave to us. I asked her why and she said she thinks my brother may have taken everything and spent it in the pub. When we found out that my mum didn't have long left, I couldn't keep up with her care needs. My brother would call past for maybe ten minutes each day and my sister stopped coming altogether in the last few weeks my mum was at home due to stress at work. I felt alone and overwhelmed. I'm ashamed to admit it but it was a relief when she went into hospital. My mum was in hospital for about six weeks, then transferred to a care home for her final six weeks. She knew it was the end. She begged me to take her home. With hindsight I wish I had found a way to do it, but she was having lots of falls and I couldn't handle her alone. After my mum passed away, the phone rang at home. It was her bank asking to speak to her. I said she had passed away, and that I would be administering her estate and was there anything I could help them with. I was informed someone had attempted to close her account but hadn't uploaded her death certificate, and they were concerned it was possible fraud, I told them I would bring her death certificate in the next day, which I did. When I got to the bank I was shown into a room and handed over the death certificate. They explained that my mum's account had been used after she died, for over a week. I told them I didn't have access to it and the only person who did was my brother, as my mum had dementia and had been housebound for years and in hospital for months. They informed me it was a criminal offence to use a dead person's bank account. I was angry but also not overly surprised. They offered to print me out a list of standing orders and direct debits in order to get account numbers for bills etc, and to print me out a statement. When they looked at the account they asked how long exactly my mum hadn't been in control of her finances for. When I told them they both looked shocked and said this account has been used by someone regularly as if it was their own account. When they handed me the statement I was shocked. Two days before she died, several hundred pounds spent in a pub. The day she died, several hundred pounds were sent to my brother's account. In the week after she died, her savings were emptied. I asked how far back they could give me statements. They said three months in branch, but could order up to seven years to be sent out. I asked for seven years to be sent to the branch. Every day on the account there were cash withdrawals, cash transfers to him and his partner. Up to £10000 a year in supermarkets that my mum didn't like. Card transactions in various pubs with cash back. Large amounts were spent in takeaways near his workplace. My brother had an IVA, and the standing order was going out of my mum's account. His Sky TV bill and mobile phone were in my mum's name and going out of her account. There were transfers to his friends. He had a friend get car finance for him and he paid that off from my mum's savings. He paid a chunk of his wedding off from my mum's savings. There were loans in my mum's name, too. Large loans, around £45000 in total. Smaller ones too. In 2018 my housebound mother with no mortgage and a good pension somehow needed SEVENTY ONE pay day loans. All of this was repaid by my mum. After all her bills were paid and with money taken into account for shopping, there has been around £1200 a month disappear from her bank account since January 2014. It is easily over £100000, far more when the loans are taken into account. I have told him I know what he's done, but I haven't let on the full extent of what I know. He thinks I only know about him using her account after she died. I tried to talk to my sister but she doesn't want anything to happen over it. I said I would try to forgive him as I know this will tear the family apart, and to be honest I am scared of being blamed and the one who gets ostracised for doing something about it. I have tried to forgive him, I really have but to be honest it's eating me away and I feel like justice should be done. Could I be accused of blackmail if I give him the opportunity to pay some money back into the estate instead of involving the police? There isn't enough left in his share of the estate to pay back everything he has taken, and as much as I hate him for what he has done I don't want to leave him destitute. He rings every other day asking how far along the house sale is as he's broke. He has a key to the house as he has a financial interest in it, and he comes in and helps himself to things out of the fridge and cupboards that I have bought. He just turns up. It's got to the point that I've had to get cameras because so much stuff was disappearing. I must also point out that he inherited £45000 from an aunt in May last year, has already had £9000 from the estate, on top of his wages and his partner's wages (she was also claiming as a single parent while he's been living with her), so he should be very comfortable financially. Do I offer him the chance to pay some back or do I involve the police..?