your point invalid yoo

low fat doesnt make one looks younger, from far his skin is stretched due to muscle developed but on macro scale, i doubt low bf makes him maintain the 'softness' young skin looks
and it's edited pic LOL

imo, judging from his face, he is nowhere looks like early 20s, more like his username indicated, in his 30s

there is no point go beyond less than 10% bf either, unless u are in bodybuilding competition
less than 10% is unhealthy already
less than 10% is insufficient for normal body function properly
hence forget about building more muscle, it very unlikely it could

it doesnt look like less than 10% to me, compare to pictures of 10% other bodybuilders shown in bb.com
their veins is more visible when they reach 10% and less

and naturally I dont think it is achievable without drugs that short-cutting our body metabolism rate to burn off the fat
and anabolic steroid to boost the hormones hence the muscle build up or just only to maintain it
and pretty sure for females, only who consumes drugs can achieve this low in bb-ing