Before the stress of caregiving, some questions may not have been asked or answered, some family situations, may not have been known. When you get closer to some of your family than you both before, some stuff you learn is not pleasant. Add that to the stress of caregiving and it’s like a pot of water, lid on, turned up. It will boil over.
Advice I have seen says leave that stuff alone. Yep, that’s hard to do. Leave it alone. Caregivers have enough stress already.
If one of the parties is telling you that you can rely on them, and you try and they fail at every attempt. It’s easier to go it alone. When those folks tell you they are going to help and they don’t show or call, wow. The safety of the patient and the caregivers health is key. The caregiver must remain healthy to take care of the patient.