This. I agree that the issue is that he's not supporting her like a true partner, in that he's asked her to sacrifice her career for his, without making any allowances for her sacrifice and helping her.
The biggest red flag I see is that not only is he not supporting her like a true partner, but he seems perfectly okay with watching her struggle from a position of comfort and plenty. That seems to indicate a level of callous disregard that I cannot even fathom.
Have you asked your friend how she feels about this? Maybe talking about it from that standpoint ("How do you feel when he...?") will help her sort it out in her own mind.
Good idea.
I am utterly amazed that he sat back and did nothing while her loans went into default!
Did he know she was heading that direction and that her loans were going into default? If he did, it really is a massive red flag. If he didn't, she needs to communicate.