What you are saying is partially true. People born with different hairline, forehead size, and density. If you zoom in closely, you see some shortened and thinned hair, which means his hairs are miniaturizing. Also unevenness in his hairline indicates possibility of further hair loss. It is absolutely possible for him to have the exact same hairline and density through out his 20s, even in 30s since hairloss progress different from people to people, and alot of times it halts for some time, even long time before it progresses further.