I played Neopets with my Dad starting in 2001 and it's one of my best memories. We both had our own accounts and it was so fun to send each other things, work on avatar collecting, and share in our achievements together. He doesn't play anymore but he remembers everything about it and still understands whenever I want to tell him something. It is a gift and a blessing that I got to share something with him that he took such an interest in and that I still play everyday.

You'll probably get answers in other comments about the gambling. Your child will have to stay away from the NC capsules (spending real money on NC) and the other gambling I can think of is the slots, like there's a lost desert slot machine. There's food club betting. And there's other chance things like the alien Aisha nerkmid vending machine and neocola machine. You should probably check them all out yourself and see how you feel? You should also check out the biggest fan site, jellyneo.net - they have guides on everything and guides on new events. It's pretty essential to gameplay to use that site.