Building a nongaming cheap productivity machine for Dad

Hey guys,

My dad has been using the same $300 best buy PC for 10 years in his home office, and it has gotten uncomfortably slow, outlook refreshes take 2 to 5 minutes.

I wanted to build him something basic that would be fairly inexpensive (we are in Canada btw), that would handle basic office programs, outlook, google drive, and occasional web browsing on chrome.

His current tower is quite large, and uses a netbook plugged into a monitor at his non home office. So if not too expensive it would be nice to have something compact he could move easily from home to office and just plug and play with a monitor via HDMI.

I don't know if the following is feasible -

It work be nice to have this PC last a decent amount of years without requiring too many upgrades, adding a harddrive or updating the ram is fine but he is not the type to DIY this (I would be), so constant yearly upgrades to maintain the same performance with new drivers and windows releases.

I know future proofing is frowned upon but give his very minimal computer usage it might be feasible?

Thanks for the time reading this post and helping out!

Is it worth doing this or just picking up a cheap pre built PC? Are my goals too ambiguous while keeping costs low? If you have any build suggestions that would be greatly approciated, if you know the parts can be found on amazon. Ca or Newegg.ca rather than imported from the states, that would be amazing too

Any recommendations on cheap wireless peripherals would be fantastic as well, he has 2 monitors at home and work respectively so that won't be needed unless there is a great deal or something.

Thanks again!