I think Jesus's healing ministry is slightly different from healing we talk today.. Healings were part of "signs" and "wonders". When we sign, they have to point to something. They pointed to the fact that Jesus was Messiah. Today healings are part of building up Church and Jesus bringing comfort to His children. And I certainly believe He gives healing gift for certain people. But it is not something the person names it and claims it.That's actually a better example then mine. The guy clearly did not have faith because he said "I can't"
I also used to wonder about this gifts.. Let's take this example.. Jesus gives Where a Ferrari and asks Where to give it to Ravi.. This is a gift from Jesus.. Where gets it from Jesus and cannot use it for his purpose.. And Where passes it to Ravi.. Who has actually received the gift and to whom the gift is actually for? Same way, when a person is healed through another person, from Jesus, who really has the gift?