Brief backstory
DM was difficult growing up.
I have since had children and forgiven her for her treatment of my Db and I. I realised parenting is hard and she had lots of external factors for her poor mental health and subsequent poor parenting. We have a good relationship now - I've put in boundaries and they work well, enabling her to be a very good grandmother.
My DB has never had children and about 8 years ago decided he couldn't have a relationship and cut off all contact with her. He has not seen or spoken to her since.
He and I have a fair relationship. We aren't particularly close but are there for each other. He has a minimal relationship with my children. Nothing has happened between us, he is just quite hapless at relationships and I gave up doing all the running a long time ago. I feel no I'll towards him and am fine with how our relationship is.
We lost our dad young, and my DM will was always 50/50 to my and DB
This year DM came to me and told me she has changed her will, leaving the majority of the inheritance to me and my DC. She has left a named amount to DB though she has not told me any of the details.
She has done this on her own, with no help from me and has asked that I do not mention it to my DB
AIBU to keep this from him? He still regularly jokes that we will be getting 50/50
DM is fairly fit so I don't see needing to deal with her will anytime soon thankfully, but I also do wonder if anyone has had this experience? When she does pass, I have this feeling that I will be pressured to spilt things 50/50 from DB but honestly have no idea where I'll stand considering she has split it to my DC too.
Any advice or experiences would be appreciated to help me process this in my own mind
Thanks x