So my fiancé’s grandmother recently passed away due to Alzheimer’s. she was 84 and her husband (my grandfather in law) is like 13 years younger and still full of life. (Side note- this is my fiancé’s dad’s side of the family).

She was suffering with her illness for quite a number of years- at the start my GFIL and FIL took care of her in her home, but when it got too much she was sent to a care home.

My GFIL began seeing someone at least a year (that we know of) before his wife actually died, and obviously kept it a secret. Was travelling to different countries and everything with her, and she is much younger than he is.

When she died, GFIL was trying to rush the funeral because he had travel plans with his new girlfriend. It took him a while to be open about his relationship but everyone is fully aware of her now.

My FIL is totally fine with his dads new relationship as long as he is happy, my MIL on the other hand is so spiteful about the situation and refuses to accept her as her new “MIL”, which isn’t what is expected of her anyway.

I can understand that he should be happy and move on with his life, but maybe he should have waited until his wife was at least deceased?

Or is MIL wrong for not accepting his new partner even though my FIL is fine with it, and it’s his dad after all?