Looking at his gear he could use some more hit and expertise though even with his current hit and expertise he should not be having the threat issues you are referring to.
his spec should not cause him to have threat gen issues of the degree you suggest though IMO he could do better shifting points around. Unless he is having survivability issues you might have him swap to a Deep Wounds spec.
I do not see gear or spec an issue though. Even as is he should be able to generate sufficient threat. my best guess would either be his rotation or his execution of his rotation.
A log of a fight (wws or World of Logs)would be more useful to determine what the issue might be IMO. He would benefit more if he came over himself and was able to go over the issue though rather than have a 3rd party do it.
I like my women how I like my coffee, ground up and in the freezer.