Yea, also, his request sounds like he thinks that he'll be judged if he picks a certain class. He's not asking which class the army best needs, he's asking if it'd be okay to "continue to pursue a prestigious act", making it really sound like he'd rather keep his class to train and become an infil than to switch class.
When someone asks for blessings in regards to what class they pick, they should be clearly told about their IR and that's totally up to them, and you should clearly state that, as a player, you don't really mind as long as he's having fun doing what he likes. It happens that people don't know their IRs, and their superiors should let them know of them when this becomes apparent.
Because asking for permission to change class or to keep one's class is not the same as asking guidance as to which class to pick.
You did good by letting him know of the IR.