Oh dear!
I don't understand why your BiL is involved in anything to do with your mothers assets, this clearly as nothing to do with him.
He is not doing his wife or your family any good by trying something which may turn out to be illegal.
If you have any concerns take the advice of a solicitor. There are many solicitors who will give 30 minutes of their time for free, I used one just recently. You just need to ring round and find out which ones do this.
Best if luck.
I would like to meet here someone from eastern Europe
