I'm so sorry for your DH's loss.
I was close to my mom, talking to her multiple times a day as well.
The best answer for what to do to help him is to just be there to talk to, to listen all he wants, even if it's repeating the same thing a million times. I was there when my mom died (as in, I told the doctor "okay" about stopping each point of life support), and afterward, I had to tell someone, so I talked to my dad about it, and my aunts heard, and told me I should never speak of her death like that again. It took me months of counseling to deal with the fact that I was told to never talk about her death again, like I was obviously mourning wrong because I needed to talk about it.
DD was 3 when my mom passed. I told her what we believed--that Gammy died and went to Heaven, and we wouldn't see her again until we were old Gammies and died. She asked questions and I answered based on our belied system.
As far as telling others, I told a few family members that I knew would get the word out quicker than I could. Had DH been a part of our lives at that point, I'm sure he would have done that for me.
--Mimi
Mom to Lala (2004), Bonus Mom to Big Sis 1 (1991) and Big Sis 2 (1992)
Grammy to Big Kindy Kid (2011), Big Pre-K Kid (2012),
Grandbaby Appendage (2014), and New Baby Grandboy (summer 2017)