Sorry, can't help. The only lasers you can use with a Python will be a trigger guard universal mount system that are useless junk and that anyone with a Python would be ashamed to install, or something on a top mount from someone like B-Square
that preclude the use of your iron sights. Even an inexpensive laser like this BSA LS650
will work on a mount over the top. If you think he wants some other kind of sight, a good red dot
starting with something like a Tasco PDP2
can be used instead of iron sights.