Same thing for any other software, see if you can get it running in wine, and see what the alternatives are and try them out until you find a solution you like. You need to accept there may be change, and may need to experiment and hit up Google to find solutions, but solutions do exist.
From a quick Google search, i found about 4/5 potential open source options
FreeCAD would probably be what I try first, but it’s hardly the only option and seen some people complain that it feels archaic (but it’s FOSS). I’ve also seen draftsight recommended a few times, and it has a free trial but is not free.
Also apparently fusion360 has a web interface that may be usable.
As much as i dislike google, chromebooks are perfect for anyone tech illiterate that just need a simple web browser that works. Every family member I’ve recommended a chromebook to has not needed additional tech support for it, which IMO, is a truly impressive accomplishment on google’s behalf.