What anyone doubts has little to do with the game. What has more to do with the game is the dialogue that takes place in the game. I just played through the opening portion of the game in the past week. Glen definitely has a deeper relationship with Lazlo than just commander-soldier.but as a novice, you don't have any contact to the highest commander in the army, so I doubt Lazlo had personal contact with Glen. So he wasn't a father image from the beginning, more some sort of idol, which could have been just anyone.
I also wonder how you come to the notion that Lazlo idolizes Glen when Lazlo never speaks. Once again, all we have to go by is what Glen (and maybe Katarina later, I don't remember) says to Lazlo and to others about Lazlo. It makes more sense to say that Glen idolizes Lazlo, which makes absolutely no sense (which is entirely the point).