Triplets I don't know if this helps or not, but I would just like you to know that you are not alone on the DH front.
One of our family's sons died very suddenly. A case of bye mum,off out the door and that was the last they saw of him. He was 16 and knocked down by a driver on the motorway(long story).
Her husband has drunk a lot since his death and has even moved into their sons old room. He won't talk about it to anyone and just covers all his feelings with drink, I'd guess you would call it 'numbing'.
He is a wonderful guy,but is one of those men who consider themselves too 'manly' to discuss anything.
I think that you have done a wonderful job,getting Dh to the Doctors and shows he obviously wants help with things and you are open to how he is feeling,which is important.
However,it must be another worry for you on top of everything else you have to deal with,so I hope that you are looking after yourself and getting the support you need too.
What I am trying to say is, in my own rambling way,is that it is totally understandable after losing Matthew and even if its not the best way,its how alot of other people in your situation try to cope.
You both seem like a very loving couple and I am sure that you will be able to work through this together and find some level of peace.
I don't usually stick my nose in when it comes to Matthew as I feel too new to comment and don't want you thinking 'God,who does she think she is?!!!' but I do think about you all alot.x.