[stressed]

I think it would mean so much to him if he heard it from your family (since they've been against for a while). It would bond them as they'd see how happy he'd be to hear it and they'd be even more happy for you, because his love for you would show. It can be a good chance for you to make your family like him even more.

You can do the surprise+dinner+ something else too of course.

But I think it would make him very happy to hear it from them and it would be very rewarding for them too

Whatever you do will be perfect I'm very happy for you!