I agree with Mo, it will all end in tears if you get the law involved. His wife sounds like she has the reins. As a full time carer of both their son and your mother, she will have the high ground in the sympathy stacks. They have had time enough to cover any money trail, my opinion for what it is worth. Check if you can to find out who her solicitor and bank were, as a son with no will involved this should be easy enough to get access to. If nothing shows up then put it down to experience and get on with your life. Banks have an excellent bereavement team who will give you all the account detail you might need for free.
