You can't control what excuse he's going to give himself to yell at you. You can address whatever behavior that is real. So find something real in what he's said and start addressing it for yourself so that you know you are keeping your side of the street clean. We all have faults we can work on.
The house seems like a huge decision. Hard call. Yes, he may blame you regardless so you should think about that and what kind of financial bind you would wind up in by agreeing. Why do these decisions have to be rushed?
If H is still willing to get you and his family together, personally I would do that so as not to escalate things. Maybe someone else has an opinion.
Try to stay flexible about doing things differently during this crisis period as far as parties and holidays go. Present a positive spin on all your decisions to the children. For instance, does every relative have to come over every year for birthdays if there's a family crisis?
