[Space_Loner]

I'm not sure what you mean by not being able to speak to him, but when the game pauses on you like that (I, for one, keep getting stuck in a wall and is unable to move) using the recall stone might just help.
I do remember though, that Lenton wouldn't tell me I've completed the quest even when I had. It took me a few minutes to realize I had to speak to the mom first, didn't make a lot of sense to me, that, since she was right next to him and he should be able to see her.