That's a rough one! I have seen this happen a few times before, and investigated it then. The bad news is that I was able to find no way to "correct" an erroneously purchased domain name. You really can't correct the spelling; the domain, as spelled, is what was "purchased".
The good news, I suppose, is that if your friend registers the proper name, he/she can always "point" the mis-spelled domain at the correct one, and probably derive some benefit of getting traffic from visitors who might also mis-spell the name.