Zephyr, I'm sorry it's so rough for you both right now. Hopefully it's not FTD. Because then you could try talking to him and how it makes you feel when you get ground up between his anger, the care work and the grief.
I know it helped me hugely to have emotional support from my boyfriend/PALS. It might seem egotistical to actively demand that from a terminally ill person, but it's kind of what being there for each other entails.
Of course I can't put myself in a PALS' shoes but maybe some not only struggle with losing abilities for their own sake but also with not being able to provide and help their family. So maybe it helps to guide him towards how he can be there for you, still. Like a thank you nod or blink, having a bit of extra patience and - if you want to get deep - remembering that you're about to lose him and that that puts him in the rare position to comfort you in your already very real grief.
The PEG-tube makes everything much easier but I get how that's a scary thing for him. When we talked about this, I promised my PALS complete self-control over what goes through that tube (although stating that enough water is a must for as long as he actively wanted to live, without hydration it's no fun on either end). The PEG is not about being force-fed and hanging on tubes. It's a weird piercing but it can make your cheesy broccoli soup a luxury rather than an exhausting existential task and choking hazard.
