I would say he could play most games at 1440p @60FPS with max settings as i have a slightly worse rig in some aspects and i average 65-80fps in 1440p in titles like MW, Witcher 3, Devil May Cry 5, Far Cry 5, GTAV
But as he said he plays in 1080p i'd suspect atleast like 80-150fps depending on the title. If you absolutely need to hit that 100fps mark you can just tune down some AA settings and you'll achieve it.
And when it comes to your question about a bottleneck, you do not need to worry. There is none