They would be balding.
We call him, "bald".
bald man
A person without hair on their head can be called bald or hairless.
Bald? Maybe?
Such a person could be refered to as precocious.
You call them a person.
You can call me dozy.
The best thing to do is to call the person by his or her name.
A person who shaves their hair totally would be called bald. Or else a "skinhead."
No, she is not half bald.
I would call them Sir, or Ma'am, unless I knew their name.
A baldy is an informal term for a person who is bald.