Just asking the basic questions to eliminate them as the answer.
1) When did he join the clan?
2) When did you enlist in the clan operations/challenges?
In case you did not know, only players that are in the clan at time of enlistment will count towards the clan competition. So if you enlisted in all the ops/challenges when they were announced, and then added him, he won't count towards any. He has to be in the clan before you enlist.
If that is not the case, then you may want to contact Customer Support just to inform them of it. Don't expect it to change anytime real soon and don't expect it to be back filled. Better to give them the information than to say nothing.