If you want to keep it simple or get a starter DE razor (assuming that’s what he’s asking for if he wants a single replaceable blade) then I would get the below personally:

Merkur Mk34c Double Edge Razor with Heavy Duty Short Handle https://www.amazon.com/dp/B002A8JO1Q/ref=cm_sw_r_cp_api_i_fE5lEb78EC8S2

I’d also recommend posting on r/wetshaving and r/Wicked_Edge as they both will also have good suggestions.

Something like this… There are adjustable models.

https://www.amazon.com/Merkur-Mk34c-Double-Razor-Handle/dp/B002A8JO1Q