URGENT!! THIS IS LONG BUT READ IF YOU CAN GIVE ME ADVICE: HOW TO DEAL WITH DEPRESSION AND BOYFRIENDS PARENTS WHO WONT ACKNOWLEDGE IT…

My boyfriend and I have dated for the last four year, He is 25 now and I am 24. We bought a house in Massachusetts together and have lived together for about 2 1/2 years now. We have 2 dogs and are planning on getting married. We are extremely healthy and practical young adults and we are doing out best to make it independently in this world without having to fail or move back in with our parents. The stress is heavy but our bills are still getting paid and food is always on our table. After over a year of being efficient in living on our own, The past four months my boyfriend has dropped into a stage of being overwhelmed and depressed. He has begun going to see a therapist because he started to lash out on me personally and have these breakdowns where he got really angry and unreasonable. With winter coming he has gotten to the lowest point I have ever seen him. His attitudes are unpredictable and he says some pretty rotten things to me I never thought he’d say. Very manic, very uneven.
His mother is very depressed, his parents have been wanting to divorce for years but his siblings are still teenagers and so they stay together. His family are in no way emotionally efficient. They don’t talk about problems, they bottle them all up. He has been going home after work to do odd jobs for his parents every day after work and not coming straight home from work like he used to. He always “stops in” to check on them or to pick something up or drop something off. I understand his need for seeing his family regularly but they don’t help him with his serious depression. He has expressed to me he has suicidal thoughts and they pretend everything is just the same. His dad won’t even acknowledge he is in therapy. HIS FAMILY DOES NOTHING TO HELP HIM.

I have to deal with the manic attitudes, and the depression, and the complaining about the shadows cast over life, while his family gets to not have to face it. I have to bear the brunt of his depression. This has caused a divide divide between his family and I. I feel they aren’t trying to help him out of this rough period. They pretend he isn’t sad and depressed and everything is okay, they pretend not to hear when he comments about therapy or depression.

How do I act around his family. Can I express to his parents how disappointed I am with them at their lack of support for their suffering son, what do I do about being so angry and resentful that I am the only one who has to deal with this depressed man? Where are the boundaries?

Since his family tends to clam up when faced with real issues of importance or of heavy emotion how should I approach this. Is writing a letter to them rude And cold or is is appropriate and discrete? I don’t want to cause more stree for bf by creating and argument between me and them.
I want to make a big note that I lived with his family, in his families inlaw apt. with him for one year so we are close to them.

Also, he has not tried suicide, he has not told me directly wants to kill himself, he just speaks about it like it’s a feeling of hopelessness and sadness that he has and he feels close to the line of just depression and suicidal… thank god. But then again look at what he comes from, he could be withholding from me a lot.