Webfill

ok thank you

My brothers 1.5 year Minecraft creative building world is been unusable because when ever he logs into it the world seems fine for about 2 seconds then freezes then crashes. I wasn't there for the insentient but i herd that his world was 1.12.2 world with mods but he accentdently logged into the world in 1.19 or 1.19.1 and now the next time he joins t he world it crashes please some1 respond. My brother is crying from the situation and my family don't know how to fix it. I just taught him how to backup his world but he still is in disbelief that his world is gone. thank you