Probably because he has suffered from sides, or is afraid of getting them.
Yep, Minoxidil is key to this treatment, it highly increases the chances of success and anyone who has not tried it should definitely use it. People on this forum are overly afraid of sides regarding every treatment there is, without considering that sides in most of them are highly infrequent. I understand those who have suffered from them (although I bet some of them are suffering from nocebo effect) , but those who haven't tried are sadly just victims of the exacerbated fear mongering of other users thriving here. Everything in life is a risk, even walking out of home. Just give min a chance, worst case scenario is you'll get sides, but it won't ever kill you. You get sides, you stop it, and sides will go away. Pretty simple.
Alopecia should be fought with every weapon we've got, once we've assessed by our own experience that they don't cause us any annoying side effect. But try them, my friends, just try them.