Sengoku Komachi kurou tan: History buff Girl studying agriculture timeslips and encounters Oda Nobunaga and helps him with his conquest.

“Buy”

Mint with alternatives for software he might need be a good idea just like the others said. AntiX is also great option for old computers and can come with a lot of software preinstalled if you get the full iso instead of the minimal options. It has a gui package installer and the session manager comes with a bunch of different Desktop environments and one tiling window manager to switch on the go. You still might have to mess with wine for exe files and make sure the ones he needs work if you are unable to find an alternative. There are some work arounds to get windows 10 IOT (it also has 32 bit versions I think) which has long term support.