The artbook said that he was looking for eternal life. In Jaheira's quest, he will also say that immortality is hard to resist. I think his story should have been a little different. Now it's hard to say whether he wanted it or not.
The artbook was created way before BG3 released and a lot was changed or removed back then. Thus I'd have a hard time to see it as canon. Going to do Jaheira's quest again soon, I might have overheard it the first time. Thanks for pointing it out, I'm going to make sure to pay attention.
I'm not saying, my opinion is the only correct way to see it. Just voiced my personal thoughts about it.
