My friend is costantly having a problem with mods, so i'm usual to try and find what mod causes the error
Usually i load the whole modpack to be sure that every mod works altogether, and sometimes there's an actual mod that annoys even my minecraft, among these it's the Optifabric
yes, i know, the mods are too many (actually loaded 108 around but it's registred as 213), and most of the should be compatible, hell it even work.
I will be sending the log that registred the crash of the game, doesn't even start up mc at all:
latest.log
Please take your time as this is just a bug report, thanks in advance

The first part of the log suggests that the OptiFine jar is missing from the mods folder which your friend will need to add. There is also a problem with dark-loading-screen further down which I don't think is related. If it still doesn't work please do mention as it could be dark-loading-screen is struggling with OptiFine's changes.

As another aside once it does work, they will want to add mixin.world.chunk_access=false in the Lithum config to avoid heavy stalling with newer OptiFine versions.