Windows 3.11 is disturbingly primitive. Anybody should be able to get up to speed on that within one or two weeks.

All jokes aside, it should only take a month or two to completely rewrite the software for that 30-year-old machine.

Windows 3.11 was basically a very poor GUI on top of MSDOS. MSDOS at that time was only at version 3 or thereabouts.