MKey

Imo, sweet spot is 100-150$. Mechanical, solid looking keyboard - it's there. Everything higher is just money sink. Everything lower is budget moment. Got montech keyboard for 100$ and, despite one switch sometimes not registering (so I swapped that one), the touch feelings alone is extra good. But I won't go higher, no point.

As an option - give a try to Montech MKey Freedom (around $70 for Teal version) . Solid (almost 1.2 kilos) biuld with metal plate over PCB, nice "almost thocky" sound (thanks to 2 layers of insulation), decent time of response and really nice-to-touch keycaps Cons: response time may be too big or haptics may feel a little viscid (due to liear Gaterons Yellow Pro); PBT keycaps but adjustable highlight (southern diodes location) may do the trick

Maybe this MSI blue switch mechanical keyboard for 35$? Never used it so idk. https://www.centrecom.com.au/msi-forge-gk300-us-blue-switch-mechanical-keyboard?srsltid=AfmBOoqQrLk6syzfgqjTzR-ysmxT4SZV-7l-aRVy6KPDgad8A4xWS4TD I can only vouch for the Montech Mkey Darkness withGateronn Gpro V2 Yellow which is 89 for the numpadless version and 99 for the full keyboard.

I like my montech mk105dr, it might be rgb but it's customisable and I find rgb tacky so I have it set to a moderately static bright white in the software which allows for things like macros and lighting options. I chose the one with gateron gpro 2 yellow switches as I wanted linear switches which work better for stuff like fighting games and it just feels more responsive imo. It cost me 99 AUD or 66 USD. It is hotswappable, has a numpad, a rotary knob with multiple modes, has surprisingly fantastic build quality considering the price and is quite comfortable and responsive. It is a keyboard that nails the fundamentals in my opinion but doesn't have anything fancy like optical switches, snap tap and ability to do analogue inputs. Given your budget though, perhaps you want to give him something fancy but this is an ol' reliable good keyboard and I thought I'd share my experience. This is literally a metal slab though so it weighs like a brick.