From watching their reality tv shows, I got the impression Gjert didn't relent on Ingrid and it was getting to her. Ingrid would write notes to let him know he was being too verbally tough and she didn't appreciate it. The boys would, on the other hand in the same scenario, just take the verbal assaults or just tell him off.
I can only assume Ingrid just needs someone else with a softer approach to coaching for her to get back to running. That could be Henrik who's been her biggest champion outside of Gjert. I think it's time for Henrik to hang it up and become a full time coach and coax Ingrid back into it. Carry on the family legacy.