[Yakuza Ps2] I had a quest disappear on me and now I can't seem to complete it.

I was doing a quest called Unworthy Son and the guide I was following said it wasn't missable so I got close to the end of the substory but made a detour and started to make some progress with the main story for a bit. When I went back, the mission was still active but there was nothing I could do to progress through it. How can I proceed here? I really don't want to go back hours ago to a previous save.