A couple of weeks ago I posted about my brother, who lives alone in the old family house after Dad's death. He has lifelong mental health problems and is something of a hoarder. his cooker had all but stopped working, his kitchen was falling to pieces and I wanted to help him get a new one. Previously he had procrastinated/ outright resisted. Anyway, just reporting that DH and i finally managed it. We went over there, and ripped out the old rotten units. At a crucial moment where bro could have got overstressed (DH was going at it with the claw hammer) I took him out for a meal . DH has fitted a new Ikea kitchen and bro has ordered a new cooker. I think the key was working with DH who by chance has just about the best skill set for the situation. He has the patience of a saint, an instinctive understanding of anything DIY (unlike my family), and has worked with people with challenging behaviour/ autism ( I believe DH is quite possibly undiagnosed autistic- that's another story).
For me, the learning outcome has been patience, not projecting judgement (even though his environment stresses me out), and making him feel he's making his own decisions.