The open tuning suggestion is great.

I might add that there are solutions out there for standard that I think are more doable than one might at first think.

First, I think leads are most adaptble -- chording appears less so. But consider:

1. Ten chords are every major chord representd by two fingers and a thumb G - 3X34XX. It goes all the way up the neck. If you add the IV chord thus (relative to G) 3X23XX and the V chord at two frets higher, you have a progression.

2. Rhythm not only needs only three notes -- it's actually a SUPERIOR way to play rhythm.

3. I play my Em with one finger (it holds down the A and D strings at the same time).

4.I play my Am and with two fingers -- one holds down the D and G strings while the other holds down the B string (obviously the same fingering goes for the E chord).

5. The A chord can be one-fingered and if it can -- any chord and it's variations can be doe so further up the neck -- sus, add2, etc.

6. The D chord can be two fingered it's G can as well.

7. Gibson and Guild necks can be very two finger friendly -- they are narrow string spacing and you can probably hold two strings with one finger very easily.

8. Short scale guitars like guild's F30 and Gibson's J45 and LG guitars would be more two-finger friendly because their fret spacing is closer. He might even find that if he capoes up and tunes down he will get a more doable string spacing and fret spacing.

9. learn to angle your thumb more parallel to the neck and it will allow for a greater movement of fingers up the neck.

The more I think about it, I can probably play just about any major chord first position with only two fingers (and a thumb) -- the C is a stretch but if I make it a 5 chord (muting the D string) I bet even it's doable)

Just some random thoughts. Hope they help.