My Mustang Dobe is pretty badly pigeon toed on both front feet. It hasn't caused any problems yet and he has been through 4 years of hard work with me. Roping, running, cutting cattle, etc. and never took a wrong step. I think that so long as it doesn't interfere with their gaits or movement, then it is more of a visual fault. It could cause some arthritis later on if it is not properly cared for but no more than other issues. :) If it is only slight and your friend likes him, then I say go for it.
*providing he passes the ppe anyway*