High amounts of cortisol in the system can cause weight gain.During of psychological and physical stress,excess cortisol is produced and at the same time promotes weight gain, depositing fat mostly in abdominal area.
I my opinion a mix martial athlete stress level is much higher than the bodybuilders.
So you find it NECESSARY?
I'm talking about the main basics of what he needs. There is no reason to be taking pills if everything else isn't in check.
In my eyes: results = diet 80%, routine 15%, supplements 5%.
If he has everything exactly in check with his diet and routine then
I would consider supplements. Most people half ass on their diet, and their routine sucks. That's 40% + 10% = 50% less results.