On the first question, we are certainly more than mere cells. Your friend is taking an hyper-materialist stand here which will not hold up well to any sort of philosophical or metaphysical analysis. Even the atheist understands that we are more than cells. We have a heart, and a heart is much more than a mere collection of cells. We have memories, and memories are not a mere collection of cells. We have personalities and we have a will and we make choices. Such things are not simply the result of ramdom, independently-functioning cells. Biologists, and even atheist biologists, know that we are much more complex than some cells that have a surprisingly low amount of entropy.
If your friend is in court and is accused of lying or stealing or murder, I do not think that the judge will be particularly impressed by the defense that he is merely some cells. We cannot blame cells, but we can blame people for reprehensible behavior. If we are merely cells, and if those random cells just happen to commit genocide, then there is no sense of saying that this is a “wrong” thing to do. Who has the right to tell a bunch of cells that they ought not to rape women?
But I am not merely a lump of loosely-associated cells. I am a person. I am an accountable person for whom some actions are right and other actions are wrong. I am a self-aware being with the ability to select among choices whether to do what is good or what is evil. I am capable of love and cells are not capable of love. I can say a lot more on this, but it is a beginning.
God does not torture people in hell. This picture of a sadistic God torturing people is not in the Bible. God is a God of love, but also of holiness and of justice. There is real justice in the universe. I find this to be a good thing, but I sometimes do not appreciate justice when I have a price to pay for something I have done. But God is just. He has let us know that if we rebel against him and if we choose not to have a relationship with him, and if we choose to do evil and to reject love, then there will be consequences for these decisions to reject God, to reject love and to reject the truth. The consequences of these actions are that we choose to be separated from God for eternity. This eternal separation from God is called hell. People in hell are not being tortured by God, but they are suffering separation from God and existence in a world in which God is not present as he will be for those in heaven with God. My understanding of hell is that it is not a place where God tortures people, but a “place” where God withdraws his loving presence.