Anticipatory Grief

Anticipatory Grief... When I read these words today, they made SO much sense to me.
This.
This is what my husband is experiencing right now and I don't know how to help him.

When my mom died, it was sudden, unexpected.
Todd's dad has been fighting cancer almost the entire time he and I have been together.  In fact, I think he got diagnosed like 3 months into our relationship... So honestly, I haven't known Ben "cancer-free".

What I do know is that he has been a fighter and has never really seemed like he was "dying"... That is until now.

Todd, however, has been experiencing anticipatory grief for a while now.  He spends EVERY free second trying to make things perfect for his dad to the point of complete exhaustion.  He wants to spend every free second by his dad's side even though his barely opens his eyes now.

I, of course, don't deny him spending that time over at his parent's house, but also don't know how to "help" Todd through this process.