Gidday Rob. Don't forget to buy a good entry level book and a star chart. Education is the key to this hobby I think. That way, your lad will hopefully develop an interest in astronomy, not just want to look at stuff. Maybe try to incorporate it into other things he's keen on. Cross link the learning, if you know what I mean. & get your bride & other grommie interested in it and make it a big fun family thing.
With what can be seen through a scope of up to a reasonable size it's still easy to go "oh yeah, that's nice" but not have the want to continue doing it. That's how my kids are now, at 17 & 21. I wish I bought my scope years ago. Maybe they would be keen now. And make it fun. Play games and set yourselves some fun goals.
Cheers
Stew.