its a wonderful gift to have such a friendship. Of course he loves you, and yes he needs someone to look up to and to trust as well - just like we all do. Children are so naturally physical in an innocent, almost perfect way, that we adults soon start reading things into and interpreting as having all sorts of hidden meaning until they hamper us and almost imprison us.
It's a big responsibility too of course and I'm sure that you will never do anything to betray his trust. His mum will soon let you know if she becomes anxious, which I certainly hope won't be the case.