It really drives me crazy that he STILL told him another fake origin story even after they're being chased by hitmen... It's obvious just from how papa reacted to the situation that he is hiding his past, why go out of the way to make up another lie to tell ryuu rather than just tell him about the woman who threw ryuu to him?
I dont personally think the lies are going to be a problem after seeing how Ryuu responded to the whole shooter incident just now. Its pretty obvious his Papa has been hiding things from him and he knows it, thats why he says he is going to wait till they are out of this situation and then Papa will tell him everything. When he DOES tell him everything, i bet Ryuu is going to stop holding back because his primary concerns seemed to be that: 1. Papa wouldnt be okay with him being gay/bi, which he just found out is okay. and 2. They are biologically related, so he doesnt think telling his blood relative that he is in love with him is a good idea, but that'll all be out the window the moment he finds out they aren't blood related. I'm excited to see more~ ლ(´ڡ`ლ)

Sometimes, truth is more helpful. Keep feeding him lies and you will lose his trust the day he finds out. Plz papa, tell him?