I suspect she married him for love and does not care what other people think. In other instances he may be earning more money that she or fellow degreed friends.
I know a guy who never set foot on a college campus who rehabs and flips houses. He puts away $100k in the bank each year in addition to money he takes in on 9 rental properties.
If the husband is an entrepreneur of any kind most people respect that. In the U.S. financial success has a way of trumping education.
Believe it or not a lot of people would be happy for her if (she) is happy. Her happiness is likely all that matters to her loved ones.
The guy may have a great personality, is loving, kind, honest, and intelligent despite not having a degree. If she has a great career she doesn't have to worry about finding a great provider. Her success allows her to be able to focus on other traits she wants in a spouse.
Anyone who makes their marital decisions based upon what (other people) "think" is not living for them self.
Only (you) know what makes (you) happy.
Life is a (personal) journey!
The exception of course is if (she) is unhappy, in an abusive relationship, attached to someone involved in criminal behavior, and constantly keeps her bailing him out of jail or coming to his rescue in one form or another ...etc Naturally family & friends would worry.
This has less to do with his education than it does his values.