My friend doesn't have a PC or a new laptop, can he play GTA 5 with this laptop on the lowest settings (+ FPS Boost Mods and change the game files, e.g. Turn off shadows):
Intel® Core ™ i5-6200U
Intel® HD Graphics 520
8 GB Ram
Is that possible at 15-20 FPS?
Don't think so take a look at Google: FPS test and look what 15 FPS are because you get a real headache while gambling.
I think the videos from the Low Spec Gamer might be interesting for you. How much fun games can be on the lowest settings, everyone has to decide for themselves.
So if you think about the GTA running on the PS3, then you should realize that it would work on the lowest settings.
I hope that I could help you and one way or another:
Try is better than study and even if it doesn't work, you can uninstall GTA again and everything will be as before…