Yes and No. For one thing, the arms are smaller muscles and often require less frequency due to the work they have to do in the other exersizes for upper body. Generally, if he's gaining weight overall, his arms will come up as well, if he's not gaining weight overall, his arms won't come up no matter what he does.
Secondly, we all respond slightly differently due to external conditioning at any given time. The solution here IMO is to try one or another approach for an entire cycle, log the results (should be keeping logs anyway, or how do you know what's working?) and when one method doesn't work, try another for a cycle. No matter what you are doing, it won't work forever. We occasionally need to change up our reps/ sets/ frequency to cause adaptation in the body. So any advice that says "this is the ticket" is merely something that may have worked for someone at their time of conditioning when it would work. Saying "In normal Hst he would do 2 exercises on chest and 1 on arms for the tens." doesn't qualify an answer, since we don't know what else he's doing for the REST of the body, using the arms.
Remember, arms are easily overtrained and underfed.
