I think I'm on the fence as far as the FA's actions. I see two sides:

1. A caring FA who wanted to make sure a guest was as comfortable as possible.
2. People react differently when being woken, some of them in an alarmed state.

That said, If I was a FA, I probably wouldn't place a blanket on a guest, but might place it next to him/her, so they see it should they wake up.

Also, does UA actively wash pillows and blanket between each use? I recall that pre-covid they didn't, but that could have changed.