It's perfectly alright if his Pokemon have education skills and the like that he himself doesn't--basically just so long as none of them are independently playable enough that they could be apped into the game on their own rather than as a companion animal. The same rule applies for legendary Pokemon, but they are otherwise allowed. Powers may be subject to limits depending on what they are (and if the Pokemon is super gigantic, it will likely find itself scaled down in size as well). He can bring up to a team of six.