He can help poor people more efficiently using fiat currency, if buying bitcoin to help poor is his intention only. Not all poor people have internet connection along with smartphones. These are essential to access bitcoin. I appreciate this gesture but my advise is to go with fiat to help poor instantly.
More people have access to internet than bank account so your statement is not valid. Even more effective way of helping the poor is by material things like food or medicine but in terms of financial help I think bitcoin is a good way of helping poor people.