Suitable for pretty much everybody ever.
But I've spent more time playing this than he has.
Lego Harry Potter's really cleverly done. The puzzles are difficult enough to warrant some serious thought, but simple enough that I can direct my baby bro to help me out with them (okay, hold square, point at the bucket, let go, ha! Check out what you just did!) with very little confusion. The cutscenes are particularly well made, with some legitimately hilarious takes on the actual events of the books/films that both of us found funny. The only thing he struggled with was duelling (it takes a bit of fiddling to shield yourself, change spells and shoot at basically the same time), but the game's done so that he never had to duel- he could wander off and take care of something else while I did it, or alternatively, he could just drop out and go get a drink. It's really nicely tailored so that you can make your playthrough as thorough or difficult as you want it to be depending on the extras you buy or the achievements you attempt. I also particularly liked the way they split the screen- I've never really seen it done like that, and I loved how seamless the transitions between split-screen and full screen were.
Most importantly, we're halfway through our second run of the main storyline and I'm yet to encounter a single bug. No glitching, no lag, no mystical disappearing NPCs, no nothing. It's a nice change.
So, look, if you fancy a nice break from heavy combat and intensely complicated plotlines, or you have a toddler in the house with a penchance for zapping stuff just for the hell of it, this is probably your kind of game.