At first everything looks normal when he launches Tekkit legends then the Technic laucher goes into minmalized mode and comes back seconds later without opening Tekkit legends.
I heard It would helpful to see the log so I got the two last logs right here :).
https://paste.ubuntu.com/p/XyVcckS257/
https://paste.ubuntu.com/p/swFkVcgDfs/
My friends system specs:
Intel i5
3.8gb ram
HitatchiHTS725016A9
Intel (R) HD graphics
Help is appreciated, thanks!