Most hand tools we use are kliens. Most battery are Milwaukee, where I work, but that is what the company buys, I know another company that does not use milwaukee. They got burnt on some the early battery tools, and never forgot it. But most employers buy supply those.
It varies a lot. Most places expect you to show up with hand tools. Some industrial places will supply since they have such big store rooms. Nothing else, he will use at home.
I would give a gift card or cash.
I suspect he already knows some of what he wants, even if has been working one day.
Angled head dykee
Linemans pliers
holding screw driver
torpedeo
few different screw drivers
strippers, he will probably develop preferences for what he likes in those.
hand crimper is not bad, if he goes into industrial they will probably have expensive ones, same with the strippers.
needle nose pliers
utility knife
hammer, especially residential
tape measure. We also use lots of fiberglass/wood folding types
Maybe a small tool bag, I wouldn't go to big, cause he may find something he likes better. These days the open open ones with a handle are popular.
Tool puches on belts vary. They were very popular, and I think are still popular in some plants, they guys uses them like a tool bag. Many people I think have gotten away from pouches cause heavy. A small pouch on a belt isn't bad either.
I think if you show up with these on day one, you are doing ok. After the first day can always run out and get more.
Get a small to medium tool poach that he can wear. If he ends up in a plant where they use they like tool buckets he can get bigger.
If you get klein this is probably a few hundred bucks, and a good start.
As for battery tools, he will probably end using them on his own at home or side jobs. If you wanted to equip a young man for his future, every man should have a sawzall and cordless drill.
Employers usually provide meters.