He may not look at it that way.
That’s to be expected, but just reading what his vindictive former MIL is doing to him throughout all this should give him some sort of indication that he was in for a rocky road with her meddling ways.
Contentious in-laws always cause marital strains.
One of my friends had a tragedy happen to him with his first wife dying unexpectedly a few years back. They had 3 children together.
The incessant demands from his former in-laws caused him to move 150 miles further away from them and pretty much cease that relationship.