I have no idea where the info about "the kid" being a Bhaalspawn came from. I can only find a single reference to "thekid" in the gamefiles and it's in the same faction file that calls Helia "denleader" In the midst of putting together a video about the three tags but really cannot find a single thing referencing thekid's parentage of their supposed status as a Bhaalspawn. Anyone else?
I read it on RPGCodex but their thread on BG3 is 217 pages long and full of conflicting information. They seem to have found confirmation somewhere that thekid is Abdel Adrian's child and therefore a Bhaalspawn.
All of the lines referencing the "abomination" in bandages seem to belong to the Red Wizard character, who is most likely Rath Modar as Rath was a Red Wizard of Thay who was exiled to the Sword Coast because of suspicions that he was involved in a plot by the Red Wizards to retake Thay from Szass Tam. There is a Thayan necromancy subquest in the blighted village and Rath is somewhere on the Sword Coast.
That's all I have for now, if I can find the original reference to thekid as a Bhaalspawn I will post it here.