My in-laws stayed at the Belvedere some 6-7 years ago when they came up to visit us, back when we were living in the city. Not sure if they've done any renovations since, but I recall that the Belvedere was a decent, albeit old, hotel, located about half a block from Times Square. It's not very expensive, which is a plus, but if they've left everything as is since the last time I saw it, my guess would be that it's looking a little long in the tooth.
ETA: I'd love to know the age of the son and whether this is a married/family trip or a guy's weekend. While the Belvedere is situated close to Times Square and would be good for the typical touristy, sightseeing family deal, if it were me 15 years ago on a weekend with friends, I'd find somewhere a bit further downtown, closer to the action (ie: bars, restaurants, clubs, shopping, nightlife, etc.).