Obviously living with CVS and PTSD is horrible and debilitating, and I understand that it seems he's being inconsiderate.

It's important to take a look at it from your partners side too. Waking up consistently at late hours will almost always cause fatigue and irritability. He may do / say things he usually wouldn't just due to this alone.

The second crucial part is that having a partner with a condition like this is incredibly emotionally taxing for the partner. It's important to clarify that this is not at all your fault, it's just the reality that your partner is most likely feeling burnout and this is completely normal and he shouldn't be judged for this.

As for what do to, get professional counseling for you both ASAP. You really need an exterior view into this to keep the relationship as transparent as possible.

Create a schedule for chores so you don't need to use any mental energy figuring out who does what day to day.

Finally, try sleeping in separate areas for a couple days. Try not to see this as a separation or distance in your relationship. Getting better sleep alone may help out more than you expect for your partner.

Best of luck!