I think managing this depends upon how much you know the person(s) & their unpredictability, that major events can change personality completely (especially when at a late age); especially when not knowing how they will react to a situation even after years. (& when phrasing hurting replies not intended)

Perhaps tips cannot be given universally except what you have already listed. Hope your mother recovers from the relapse and that you both can weather through future difficulties!
:)