What should my FIL do?
Background: my DH's parents divorced when he was a child, and years later FIL met and married his second wife. Second wife had two small children already, who called FIL "dad", although they were not his by blood. After 25 years of marriage, FIL and his second wife divorced fairly acrimoniously. The divorce courts ruled that FIL and ex-wife #2 must split their assets 50:50, with FIL allowed to keep anything that was his before the marriage. FIL worked extremely hard throughout the marriage and financially contributed massively more, with the ex-wife only working full-time for around 5-6 years. FIL was able to stay in the matrimonial home by paying ex-wife #2 50% of its value. Fast-forward 5 years and ex-wife #2 passed away without a will. The son of ex-wife #2 struggled with her death and so his children (his own wife had died a few years previously) went to live with FIL (their grandfather) temporarily. However, before any inheritance was claimed, the son also died. Ex-wife #2 died with most of the money she received in the divorce, in the bank. The ex-wife #2's daughter, who doesn't have children, has therefore inherited all of ex-wife #2's money, which in reality is pretty much all of my FIL's money. My FIL is now bringing up the grandchildren, therefore my DH and my FIL's thoughts are that the daughter should give all of this money back to FIL. However, she has only given back 50% of it. AIBU to think she should give FIL 100% of it, as it was his money to begin with?