Ditto to what Jo said
A good litmus test is to try a nap every couple of weeks or so to see if he still needs the help (some LOs do...mine needing httj until 5.5 months). Naps usually get better ~6-7 months, so if he's still needing the httj for every nap by then, you might doing less and less to see if it's a prop issue.
Good luck! Enjoy the you time with those long naps!