If you give a person a good fundamental understanding of what to use and when, without complicating things (and let's be fair, "Use X when you are tanking lots of adds or something that hits fast, and Y when you are not" is not complicated), then you are giving more valuable advice, something that a person can use to further their understanding.
Give them good, solid advice -- and if they ask you to dumb it down a notch, then do so. Don't automatically assume he's too dumb/unmotivated/whatever to get it. Your assumptions are just that; assumptions. He could be a returning player, or perhaps using a Paladin as his alt -- you don't know, and you shouldn't just assume that he doesn't care.
There are two ways of doing things, and if you are going to spend the time doing it, then you might as well choose the right way.
I'm teaching him to fish, and you're giving him frozen supermarket fish sticks. If that's all you have to offer, then you should not give advice in these threads.