So. Why is this happening?
They can put thoughts straight into his head; he’s noticed that, which is some evidence about exactly how much mind control they can do, but he might not have noticed it every time. Is there anything they can’t do? If they’re the people who had him before, it's noteworthy that they didn't do this before. Did they just gain the ability? Were they holding back? Why would they hold back? To have something left to convince him they're not the same people? (In that case, they do need to convince him; they can't just make him believe them. And they can't just make him take whatever actions they want, or at least there are limits of some kind on that.) Are there other possible reasons to hold back? Maybe they can only do so much outright mind control? (In that case, should he make them waste as much of it as possible on him?)
So why are they being nice? To get him to trust them? Genuine kindness? Are there other options? Do they want him out of sight in the shelter? Maybe they do. Any other options? It’s hard to think. Can he tease these options apart? Wanting him out of sight and being genuinely kind can maybe be distinguished by whether they offer him nice things in view of other people. Trying to win his trust for something nefarious is the hardest and most important one to distinguish, since they can just act exactly like they would if they were nice people right up until it's time to stop doing that.
It’s hard to say what to do about that. But he listens for signs of people gathering nearby.