If you're the DM, (which I assume you are, since you said he's going to be an NPC), I wouldn't worry too much about the exact mechanics. Look at what the party has, and put him a bit lower than them. It's not like your players are going to proofread it, after all.
Give him Darkvision equal to what one of the PCs have, and don't worry about racial modifiers. Just push his stats to where you think they should be to go with his personality. From the sounds of it, I'd say lowish Charisma and Strength, higher on Wisdom and Constitution, since he did survive having his wings cut off. I wouldn't give him any Dexterity bonus since his wings should have been a balancing factor for his body structure, and without them he would have more trouble moving quickly. Something he would have learned to deal with and as such wouldn't incur a penalty, but would prevent him from getting a bonus. I wouldn't give him a Jump check bonus either.
Wings that don't work have about as much game effect as his shoe size, so I wouldn't even think about them. I wouldn't give him any Spell Resistance at all. It always felt like, at least to me, that was tacked on to make them more menacing as villians, which you shouldn't have to worry about. For good measure, let him use the drow spell-like abilities once a day at class level. They're not exceptionally powerful, and they'll remind the players that he's part drow.
And just for flavor purposes, does he have hollow bones or solid, marrow-filled bones? I would go with solid, having to with having the Constitution to survive having his wings sliced up at a young age.
Just my thoughts, hope they're useful.