When my parents died very close together I honestly could barely put one foot in front of the other. I was limited to four days bereavement leave, but absolutely could not face work for a few weeks.
Even then, accomplishing anything the least bit difficult was not possible. I just sort of plodded through the days. And I had a senior position.
I would cry at almost any expression of sympathy.
I am not sure what helped but I think it was time. I did speak to a bereavement helpline a few times and their reassurances I was normal were helpful.
DH was amazing. He stepped up and did most things really for a couple of months. But our children were grown. Had DH not been there I don't know what I would have done. Survive I guess but it would have been much harder.
I also found an online grief support group and posted there for awhile.
People on there were great.
Everyone grieves differently. Do you have a bereavement helpline or similar? I found that easier as it was not a commitment to showing up at a particular time.
Is your husband talking to anyone about his loss? That can help.
I found easing into routine tasks was the best. Nothing challenging.
Would he benefit from some short term sleeping or anxiety meds? Sleep was a big issue for me as I cried a lot after I went to bed.
He has to find his own way. Keep making gentle suggestions but not too many. Can you pull him into an activity you are already doing so he doesn't have to take initiative?
I am sorry for your loss OP and for your husband's struggle with it. I hope he can get his head above water soon.