How common is it that spirits can materialize into a physical form/appear to you in a way that you can actually see, hear, and feel? A friend of mine who's a spirit has done it in the past. He did it to pull me out of the way of an oncoming car, stop me from falling down stair after tripping(this has happened on multiple occasions), stop me from falling after tripping or slipping, and helping me up if he was unable to catch me from falling. Sometimes when he does this he'll say something, and it sounds like he's flesh and bone(is a living person) as in I can actually hear him.
Most of the time, he doesn't materialize. I hear him in my head, I see him with my mind, and when he touches me I feel a tingling sensation where he touched me.
Is this normal?