It seems to me like you have done everything that you can do at this time. You have let him know that he needs to seek help. The rest is up to him. You cannot force him to do anything that he is not ready to do. Believe me, I know the feeling of being helpless to do anything. Especially when the other one does not want to do it. My husband has been diagnosed with Major Depression and a bunch of other things, and unless he is ready to do the things that he is supposed to do, I cannot do anything but be there to support him. That is the only thing that you can do at this time. It is very frustrating, I know, because you want your ex-bf to get better...it takes time.
As for not walking on egg shels about things, i think that is a very good quality, even though it is brought on by your ADHD. You should say what you are thinking.
Its very difficult to help someone who is in a depression. But, remember, that once he makes the decision to get the help, he will know that you are there if and when he needs you.
Also wanted to mention that you should NEVER give up your identity to please someone. You are who you are, and that is what makes you a great person, don't ever give that up for anyone!
There is light at the end of the tunnel for everyone, although some take longer to reach it, it is there.