The following is an option, but it does require you to be assertive and to change the way you feel about his comments (easy to say, not easy to do
)
Laugh at him. Make it clear you find him amusing in a slightly pathetic way.
oh, you're doing the criticism dressed up as concern thing, I love that. You're so funny.
If you can name one of my friends, my favourite food or any of my top 5 favourite songs, I'll give you a million quid.
Oh bless you, I don't care what you think about anything.
I should have brought my barbie so you could pull her head off, brothers eh?
or let him go on and on and on and then go hmmm? oh, half past three I think.
But certainly challenge him on comments about your children, whether or not you feel up to poking him with a stick generally
they need you to do that. "What did you mean by that?" "It's rather inappropriate to make such kind of a remark to a child." that sort of thing.
Or you could duck out. Hell, you could say no, I'd rather stick pins in my eyes than have to suffer him for an evening.
And - if he comes to your house - there's a solid object between you and him and you can choose to not open it.
You can't change him. You can only change you.