I think it depends.
If you (or dh, more importantly) are in a place where you're ready to cut then out entirely, take a stand and don't invite them. They haven't shown themselves to be loyal or deserving of your respect.
If you're not in that space yet, or still want to be seen to be doing the right thing, then by all means send the invite, but do it expecting nothing in return. That way you won't be disappointed and anything else will be a happy surprise.
I'm really sorry your bil and mil are so selfish and untrustworthy, but it is what it is. You can only control your own actions.
HTH x