This fight seemed impossible without the perfect setup and I don't understand the purpose of the 2 npcs helping you, when they are only lv1 and almost do nothing at all.
If you have at least 1 healer and use all your resources (bombs, arrows, anything) to CC Alexandar for the beginning fight, that part is a joke. After you break his armors you can perma cc him and just wail on the rest of his friends until you win. Once the worm fight starts, you have to just be careful and not group up, then at most the worm will hit 1 party member. Use potions to stay alive if needed and just hit the worm. It is only 1 thing, if you're apart it can't hit more than one person at a time. It will eventually go down.
That said, Leadership helps a ton with the initiative issues. I put a lot of points on Ifan into wits to discover secret stuff and for some early cc (sleep grenade is fantastic at breaking a lot of magic armor). So he went first. I used him with adrenaline and grenades to sleep Alexandar and after that the fight was cake. Being able to keep the ring that teaches you restoration helps a lot.
