What would he say if you told him you had made him an appointment and you are going with him? If he gets anger and says he's not going, it's time to think about yourself. I should have walked out 15 years ago, now it's 41 years later. While my spouse did seek help, his depression/mood swings/anger is just as worse now as it was when he was first diagnosed. Maybe a separation instead of a divorce might be what is needed to force him to seek help for his depression. If you're separated and he still refuses to get help, get on with your life. I know all about the stress and what it does to your health because I have years of experience in living with a depressed spouse.
Good luck
Betty