That Wii is most certainly not new. All of that crazy error stuff, and mention of "Homebrew", means the Wii was illegally modified by it's previous owner. This is assuming it was bought used, and your son didn't do the modifications himself.
Regardless, if pressing any buttons does nothing to get rid of this screen, it's likely the console is "bricked". This essentially means it's been broken permanently, most likely with no way to fix it. The hardware modifications also mean that Nintendo may refuse to repair it... worse still is it's possible the seller was intentionally selling you a broken Wii, so getting a refund may not happen, though I'd still recommend looking into it.
My apologies for being the bearer of bad news.