He's got everything on very high he says. So that'll be why
Thought so Highest settings in games usually aren't worth it, so it's always best to settle for very high/high instead of ultra. There are countless examples where we'd be hard-pressed to spot a difference unles staring at a rock for 15 minutes. PCSS looks realistic but no way is it worth the performance hit, same with HBAO+ Ultra.
Tell him to dial in my settings and report back, should be a lot better and without a significant visual hit