Welcome back, I read your account of your husband's behavior from back last April in
Welcome and orientation /
Family coping with family member with depression
and it sounds as if things have changed slightly but are no better. Additionally medication often needs to be adjusted over time and this is not happening, perhaps losing some of its effectiveness as a result.
I'm afraid you still have the same problem as always, simply put you cannot make a person go get professional help, and most often it's not going to be properly effective without their own desire to go, after they recognize there is a problem.
I can only ask if there is someone else he respects whom he would take notice of?
I guess the most important thing you can do is to look after yourself properly and draw boundaries, for yourself, son and grandson. This does not mean arguing, but more likely when his behavior is unreasonable, angry or belittling for you to simply say you will not be spoken to like that and walk away.
Can I suggest medial support for yourself if you do not have any already, apart from your diabetes and high blood pressure that is. Having a walking-on-egshells life is terribly stressful. I'd also suggest ringing Relationships Australia on 1300 364 277 who may be able to advise you as this is, as previously described, an abusive situation.
Please let us know how you get on.