My suggestion before you start off with the whole set up is to plan a budget. Ask other experienced people regarding equipment and such. You may want to spend extra money on equipment such as lighting, pumps, filters, sumps...etc You want to be happy with the equipment you get at the end of the day because trust me you will always want something better. Fish and coral dies, equipment doesn't (eventually dies).
Cheers and Happy early Christmas present to your son
He will love it for sure!!
Tan