Man of Honour
Of what?
All i've seen him post is that he's expecting a 50/50 split of inheritance. That doesn't appear to have changed at all.
If his mum has chosen to gift/sell some of her property now, that's the OPs (or your) own assumptions coming into play, assuming that meant 50% of the holiday home was coming his way.
Oh dear, you're really going down that route
Perhaps it was 50% of her TV.