In the cave where there are gnoles there is a chest, in the chest there is an item, I do not know what it says in english, but in my language that item "turns enemies into friends", if u use it, then beholder appears. I thought maybe I could use it on a this drow... Idk. Has anyone tried to do this?
It's just faulty translation (as it often happens); this item's description says
"A flask that can hold friends and foes. Likely to make the former the later"
so friends - to enemies.
By the way, it's not a Beholder - just a Spectator (lesser type).
Actually, your English is good enough, don't ruin your playthrough with a poor translation:-)