Abraham didn’t understand God very well (at least not early on). I don’t say that as a dig against the Patriarch. I don’t think any of us understand God very well either.
When Abraham discerns that God is going to destroy Sodom and Gomorrah he is bold enough to attempt to talk God out of it. To his credit, he seems to have genuine concern and compassion for the people who lived there. He does not want to see them destroyed. Of course, his nephew lives there, so that is an added motivation. But I don’t think we should assume that is the only source of Abraham’s concern.
I’m not so sure modern Evangelicals would plead with God for mercy toward a notoriously wicked group of people. Sadly, we’re more likely to start gathering the firewood for the roast. And we tend to be more like Jonah pulling up a lawn chair with a bowl of popcorn to watch those sinners get what they deserve.....................