Some things are a given in such circumstances. If they did not have an interest in firearms, they would not have approached you about them.
My first question when this happens to me is always, " How much experience have you got with guns?"
What follows next is a session in my gun room if I know them well or meeting at the study room of the gun range to discuss shooting safety, various gun types and other things.
Then we go to actual live fire.
When at the range, I always have a few guns of various calibers and types. My range bag always has at least three caliber guns inside and both a revolver and two autoloaders A person can shoot those and get some idea of what type gun they like best, what caliber fits them best and will usually walk away wanting to buy their own gun soon and always ask when they can come back to the range.
I do not consider it mentoring though. There is not any active shooters here that has not done the same with several people over the years. I did it with my mother, three daughters, two of my high school teachers, a college professor, a few friends, a couple neighbors and I think other shooters would be much the same as far as leading a newbie into shooting.
If we did more of it, there would be more gun friendly people ready to vote on our side for gun rights.