Decide on the type first. Brands come later.
For practicality, a white face and black hands are easiest to read, in a glimpse of a fraction of a second.
Black face and silver hands come next, and are common on military styles.
Gold, silver and coloured faces are more difficult to read, some might say less classy.
A stainless case will keep its looks.
Chunky metal bracelets are a style choice, but wear out the cuffs of your shirt, are heavy, and difficult or expensive to resize (he may still be growing).
My own preference is a leather strap that is very easy to change, but I am old and he might not like that,
I'm told giant dials (35mm or bigger) are going out of style.