Hi and
to IIS!
The only problem with a reflector like a dob, is that for terrestrial viewing the images will be upside down.
Unfortunately, any decent refractor on a decent mount will be well out of your budget. You could potentially get a cheap scope for terrestrial viewing but ultimately for astronomy it'll be mostly disappointing, which will either make him want to upgrade soon (when he can get a dob for astronomy and keep the cheap refractor for daytime viewing), or it will make him give up in disgust.
I hope it's the former and not the latter!