The guy was a wimp.
To those of you who don't understand the question, the number refers to the diameter of the high E string, in thousandths of an inch. Look at your string packages.
I guess if your arthritis gets real bad, going for 10s [or lighter] might help some. It would take more tension off to tune down a semitone and capo at the first fret. Poor workaround, I know; but if it helps someone keep on pickin' ... :)

cheers
Dennis