Beginnerguitarist.com

www.justinguitar.com

Simply the best

Cannot recommend this site enough.

Depending on what his goal is. If classic guitar, then lessons are prefered, at least at the beginning. Does he have any music background? I mean, does he know the notes. It would help him identify the notes on the guitar.
If he just wants to know the chords, the sinmple research on Internet or any basic book. Keep it simple. Once he gets an idea of the chords, he will master it quickly.
If it is more towards electric guitar, then there are plenty of youtube videos. He can either search for basics and exercises for hands and fingers, as well as searching for a specific song he wants to master.

We got Rocksmith (xbox 360) for my son a couple of years ago. He's actually coming along pretty good. I think his main problem is that he's fooling around with Trumpet (HS Band), Piano, Guitar and Bass Guitar. He's passable on all 4, but he just can't choose

A bit like somebody fooling around with swimming, biking, running without being able to choose one?

i can relate to that. I play drums, guitar, ukulele and vocal chords (I sing). I am not very good but I may not be better if I concentrated on one instrument. Or maybe I would but we will neve know because I don't intend to give up any of them, they are all fun. I want to add one, actually, I'd like to learn the piano.

He comes by it honestly. My list (in chronological order):

Accordion, Harmonica, Sax (Alto, Sorpano, Tenor), Piano, Baritone TC, French Horn, Mellophone (F Horn mouthpiece, tho) and Clarinet.

I picked up an old garage sale trumpet so he and I could learn together... but the trumpet mouthpiece never felt right. Too wide/shallow.