I used to have model boats, and ran Billings and Caldercraft tug boats.
I really enjoyed building the model, making it as realistic as possible and then running them in events such as steering competitions etc.
Whilst I really enjoyed it, I don’t think that side of the hobby lends itself to to quick and easy fun on the water.
The kits could take quite a lot of time and effort and due to the boats being true to scale etc; they weren’t fast and exciting to pilot and only really made sense if you enjoyed the building phase and entered into competitions and / or joined a club.
Running my Billings or Caldercraft tug around an empty pond would be like watching paint dry.
If you want quick and easy fun, get him a speed boat model.
I’ve never bought from them, but the Cornwall Model Boats website has a good choice for you to have a look at.