I need to let go so I can sleep

I do think you should ring the bank and also see a solicitor. If she has been taking the money after the mother's death that is fraud. Have the pensions people been informed? etc etc.

I totally sympathise with you and others Loobs we were left in a very similar situation when DH’s parents died. There was a small property (very run down so not worth a huge amount) plus a valuable collection (I best not say what it was) that was suddenly gone. DH’s wealthy brother and witch of a sister took the lot. He was fed a story that his mother had borrowed money, so the property was signed over.... (pure lies as we know there was no way she would borrow anything from anyone and lived very frugally) DH was handed his mother’s wedding ring by the priest after the funeral. We returned home with it and DH posted it to his sister with a note saying “you’ve got everything now...”

There is no way my DH would fight over anything. It did eat away at him for a while but not long. He just took the attitude that he hoped the pair of them enjoyed their ill gotten gains and will never speak to either of them again.

As others have said. Very sad when siblings cheat each other like this.

In law, if there’s no will, the money belongs to surviving children shared equally. Your sister in law is breaking the law.

If you know the name of the main bank then your husband must phone them. Ask to be out through to the bereavement section and tell them your MiL died on ...and name the date. The account will then be frozen and only certain expenses eg funeral related, be allowed.

Tell your SiL you will start legal proceedings if she withdraws any more money.

Either that or just let it go and let her have the money.

I agree with OldMeg you have to decide how far you want to take this. If what your sister in law is doing is indeed illegal then do you want to bring that to light with all that entails.
Can you be the bigger person and let it go. It's very hurtful when families behave this way to each other I know.

I couldn't sleep at night either, knowing that.

If husband didn't do it, I would inform the bank myself, as the account should definitely have been frozen, even if this woman was legally the sole beneficiary!

And presumably, if a crime is suspected, the bank will then persue it as a matter of course.

Once the bank is told someone is dead the account will be frozen. My sister and I were the only executors and only beneficiaries. I was advised by a friendly solicitor to take out loads of cash before telling the bank of her death as I would have expenses I could not otherwise fund. It was very good advice. I made a record of every penny spent. I also got probate in record time without paying a solicitor. My sister and I get on brilliantly and as she was abroad at the time of our mother's death she left it to me to handle it.

loobs I think your Mil knew what her daughter was like and hadn't got the strength to say anything about it and have to face any rows or bad temper in her last days.

I had 2 aunts who systematically kept my mother out of all the deals they made to get their hands on all the parents' money.
Jewellery goes to the daughters at least the first choice.

Well, lots of advice, thank you all so much. In the end I managed to persuade my husband to phone the bank (who had been informed) and the ISA firm (who hadn't) and now we will just have to wait and see - funeral in a couple of days so will see S-i-L then and maybe get an idea of which way this is heading. I have told him it isn't fair to confront this at the funeral/wake or even on that day as she was close to her mum (he really wasn't) and it would be
unfair. I do heartily concur with the sentiment that holding on to anger is like drinking poison and expecting the other person to suffer - brilliant. I am learning to meditate (every cloud!!) and managing to 'let go' whenever I start to feel annoyed - hopefully this will be resolved easily.

Anger, bitterness, ruminating give it any name you want it all has the same outcome. So the big question is how do you get past it? I think perhaps you already are you posted this it means you are talking about it and that helps get you past it.

This sounds too simple but before bed and when you wake up try thinking of at least 3 of your blessings whatever they may be. It helps remind us that despite ugly things happening we have so much more to be happy about.