Like anyone who has to deal with the control diabetes can have on your life.it can be very hard to appreciate the good changing your life and taking that control back will do you!
I found it hard the first few days was angry and just didn't want to accept that there were things I just couldn't do, however I then began to appreciate the diagnosis in that rather than the diabetes controlling my life, I could take control and make the changes that not only suited me, but made my life healthier! yes it is easier said than done, its not good when you crave something and just know that it will make you feel like crap.
It may do him some good to speak to a counsellor and let him air his frustration, anger, resentment at someone who wont judge, or advise him.Someone who will just listen to what he has to say and help him find a a better way of dealing with all the pent up emotions.Someone who can be there whilst he endures the roller coaster that is his life. I have to say, that I am certainly not saying you don't provide this, but we all know how attached a family member is to the situation and its often easier to really offload to a stranger. I know it may be hard for him to even consider it, but if he perhaps grabs hold of the notion that his life could be better and that both of you could be much happier, then he may just want to try it!!.I think every single one of us have mood swings its part and parcel of diabetes and if some ones levels aint good it dont help neither.