He does not let them go to hell. There is this marvelous thing called free will. God would love to save us all, but we, through our own actions, show that we do not want ourselves saved. God would send miracles and visions to everyone if he thought that would save them, but that won't change people's point of view. Think of the three witnesses. They all fell away in the end.

Tell your friend God's love is indeed infinite. Man is the one who chooses if he goes to heaven or hell. God cannot pick for you, that impinges on free will.