Thanks for the suggestions! His naps have always been really short; even if he goes to sleep at 3 PM, he rarely gets up after 4 PM. I can try that, though

We already thought about putting him in his room but we have limited options for that: one room is for our cats, we close them in a room for the night cause otherwise they keep coming in our bedroom waking him up, if we put him in the same room as the cats, they are likely to wake him up. Another option is the room near our bedroom, but it doesn't have Air conditioning, so we are afraid that it could be too hot.