I doubt that Dooku's link to Qui-Gon could change his mind at that point; Qui-Gon was still alive when Dooku started to cooperate with Sidious. But if Qui-Gon would be eager to help Dooku change the Republic, perhaps Dooku would chose to attack Sidious along with Qui-Gon. I don't think that Sidious power would be something, that Dooku would be affraid of at this moment. I mean, it's not like Dooku and Qui-Gon would beat Sidious, but I don't think that fear of Sidious' powers would take control over Dooku.
If Qui-Gon would promies him that he will leave the Order, that he will help him to change the galaxy and that he will be training Anakin under Dooku's guidence... I guess that could be enough for Dooku at this state of mind.
I'm just not fure if Jinn would be eager to do or at least say that all.