lost saves

Year 6 save file lost today after repeated game crashes. Started solo and was in Co-op when dashboarded and the world was just gone. Game crashed, reloaded, Connection failed. Second restart and no save files. I don't think theres any hope to restoring it.

My son (13), plays on his PC threw steam, twice now he has lost all progress. The first time was only 30 house the second close to 100 hours. We're not sure what's happening, neither of us are super computer savvy, tbh last PC I owned had windows ten. Anyways. We can find the files on the...