No, I would not condescend to him. I was sincere. My mother was an independent believer - that is, she took from the doctrine what she considered good and disregarded the rest. Many self-identified Christians think that way, whether they say it or not. I was brought up in a mixed Christian family, attending both Catholic and Protestant churches - and finding much to appreciate in both. When I was old enough to read the Bible, I rather liked the Jesus character (very few others in either book, I have to admit) and thought he had some sensible things to say. (If only he hadn't been so childish as to curse that fig tree and the pigs, I'd have admired him.) I liked many of the teachings. At that time, I didn't know that so-called Christians generally ignored them.
I'm 100% sincere about the reunion argument being the most persuasive for eternal life. We don't obey the law because we fear punishment - nobody expects to be caught. We obey it because it makes sense. We want to go to Heaven, not to escape Hell or to be rewarded or to hang out with God, but simply to continue and have our best relationships and best earthly experiences continue.
That's a very seductive notion. Hard to give up. Long after you realize it's just another bogus carrot, the after-image lingers.