Am I missing something or is there a way to get your companions to autonomously use stimpacks or do I have to talk to them and tell them to do it each time? I've had a few close calls and I thought just putting a few in their inventories would solve it but they still wouldn't use them.

They're supposed to use them automatically when low on health.

Keep in mind you have to put them in their inventory for them to use them.

You do? I never put any stimpacks in my companions bags, and they still let me use the heal option in the companion wheel. Or do you mean to heal autonomously?

Yep. They can hardly reach into your pocket in a firefight, right?

I guess they just weren't quite hitting the threshold yet. I'll have to try again.
Also will use stimpacks to heal himself? Doesn't make much sense but I saw you can use them to heal him.