I’ve run Speedplays for years on my road bikes and they are great, but keep in mind the cleats are fairly pricey. Speedplays are otherwise super reliable and the float they offer is a nice benefit.
One thing to think about is if he starts to get serious and wants a power meter, power meter pedals are likely a great option since they can be easily moved from bike to bike in the future. So perhaps starting him out on the Look Keo’s, before investing in a set of Speedplays, may make some sense.