"Am I missing some boundary that I should be setting?"

I don't think so. It is his choice to go or stay. As long as you are comfortable with that.

"Our MC has asked me, twice now in front of H, what my "timeline" is for all of this."

Not sure why he is asking that question. I don't think there would be an issue for him to tell you why he is asking that question. Ask him.

"He felt good about it. But also, H states he still doesn't see much hope for us."

So.. there is some hope.. even though it is not much?

"I feel so down today. Alone."

I know.. it sucks. Just do your best to try and keep your mind busy.

Relax
Eat
Think
Act normal
React.. Smartly.
Do something different.
Emulate.
Do Work.

Lets get "RETARDED" in here.