he only wants to challenge what I said because I mentioned God in it, and presented an explanation for why God wouldn't intervene in human suffering.

I did no such thing. In fact, if there is a God like your religion envisions it, I do agree with your explanation. Only by knowing suffering we can understand happiness, so God cannot remove suffering at least not without making us lose a significant part of the life experience that makes it valuable. The concept of God creating sentient beings with free will and that will have to experience life even through suffering makes perfect sense. The atheist argument of "there's evil in the world so there's no god reeeee" is not a good argument. We wouldn't know good without knowing evil.

I was however responding to your claim that:

Humans are designed to suffer. Suffering is an intrinsic quality of life.

I disagree with this.