My folks have a crazy codependent relationship. My dad has been depressive for 30+ years, and my mom plays the martyr role, picking up the slack and making sure everyone else knows about it. As the years go by, my feelings about their arrangement change, but ultimately it's their relationship and they're both getting something out of being together, and if not, it's beyond my control to change them or their dynamics. Unless you suspect elder abuse, it's should probably be considered out of your hands.