HardSurvival

So when my friend enters either a server or a singleplayer world while playing the original tekxit 3 it closes minecraft with no error message and re-opens the technic launcher does anyone know a solution ? I've tried everything we found, a lot of it was about the RAM he has but he tried to use 3GB or 5BG even 16GB out of 32 and none worked. Pls help :3