My FIL and MIL split up 20 years ago but have never actually divorced. FIL (DH dad) made a will but DH worried that as he is still married his ex (DHs step mum) will still be entitled to half his assets/pension etc. The will won’t benefit DH so he’s not concerned for himself but worried about his half sister (who is the DD of both of them) Can anyone advise please?