Your son should hold off the proposal and cool down a little

In you old post, the girls' parent only buy a house for the girl not living with the girl! The girl cares your son more than your son cares her. She will regret eventually. Why not let both of them separate a little to cool down. Then they will have a better decision.

Your son now buys a ring when the girl is leaving...... It's a joke.

Two good and successful persons doesn't mean a happy family.  There is no right or wrong on this subject. The girl's parents just want to make sure their child is not the one who will be hurt most. If they really interferring the girl's life, you should see the fights between your son and his girlfriend.

Don't referrence your student's case. She grew up in a divorced family. She probably is more mature than your son's girfriend on this subject.