This is actually his issue not yours. I'm so sorry for all your losses.
The hard thing to do is not take it personally. You've had a lot going on and you've said he was supportive during that. DH and I have had a lot going on at times (bereavements and historical sexual abuse with family members) and when I'm feeling angry and frustrated at lack of support for me coupled with unnecessary drama with his family causing me to have to support him, I find him unattractive. I'd never tell him though. He's not unattractive at all, he is overweight but it doesn't bother me at all when I'm ok and he's ok. When we are emotionally at a low and he's annoying me I do look at him physically and think he's fat and if he eats icecream or something I think 'ffs'. I sound like a complete bitch but honestly I'm not, and I always tell him he looks lovely (he is very handsome, to me anyway) and I'd never tell him his stomach is unattractive. And it isn't unattractive to me unless my emotions are not in a good place. I don't know if any of that makes sense - just trying to say it's not you, it's him. But it was cruel and unnecessary to tell you and shows lack of self awareness on his part. His ED is nothing to do with your weight and I'd imagine it's everything to do with stress.
It's very hard to keep going through what you've been through and I think you both need support.
His lashing out at you when you're down is shocking and I'm sure the last thing you expected. Who knows what's going on inside his head. Is he angry that you haven't had as much to give because you've gone through so much? Is he unable to cope with being supportive through such a terrible time for such a long time? Does he also feel bereaved as he knew your family a long time but he feels he can't show it as his loss is nowhere near as great as yours?
Have you had any counselling yourself?
Coping with death is probably the hardest thing we face in life. I'm not saying your DH isn't completely out of order and an arsehole, he is, I suppose I'm hoping to help you see that it's not something to take personally. I don't think it's about your weight at all. In fact, you don't think it's about your weight either, as he was able to have sex on the occasion you mentioned. So it seems much more likely he was lashing out and hurting you.
If he has form for lashing out and hurting you and blaming you for things that are his responsibility, that's a big problem, a complete arsehole and bordering on abusive.
If he doesn't, I would say you've both been through a hideously stressful time and the cracks are starting to show. You both need help and support. The grief doesn't go away, even now this morning I could cry out of loneliness for my DF and he's dead for over 10 years and I've lost 2 more immediate family members since then. It's shit. When the person I was closest to died I just wanted to die myself and if it wasn't for my DS I don't know how I would have kept going. All my joy went out of my life. I've no idea what that was like for my DH, but I do remember him looking at me and trying to talk to me about it and I just couldn't respond or care. It all seems like a blur now.
I'm really not sure if any of this has been helpful. I'm sure it feels like he has kicked you when you're down, and that's a shocking shocking thing from the person who is supposed to be your greatest ally. He needs to grow the fuck up to be honest. But don't take it personally. It would be better to be angry with him about the unfairness and injustice of what he has said. Easier said than done!
I think women are socialised not to say things we think are hurtful to another person. I do wonder how he'd take it if you said he was skinny or scrawny or weedy or something similar...