Re: Got my son a wakeboard package...
More like 18-20mph... anything slower than that really he'll just sink back down into the water and your boat probably won't even be on plane.
As far as getting up, rallyart pretty much covered it. Only extra I can add is having his arms wrapped around the outside of his knees, very similar to a cannon ball position. Just need to hold that and let the boat pull him on top of the water, standing up before hand will only result in catching his front side toe edge and face planting.
Its similar to snowboarding, but also very different. Snowboarding there is a fine line on how much pressure you roll onto the balls of your feet for your toe edge in order to have a nice turning transitions. On snow, you want just enough pressure to turn your toes white, while wakeboarding... your going to want an aggressive toe edge which takes a lot to over come if he has snowboarded a lot.
I wakeboarded for a while before I even tried snowboarding, it took me at least 3 different outings to finally figure out how much pressure to apply for my toe side transitions. Once he figures it out, he'll be hooked, nothing like the feeling of wake to wake jumps.