Red actually complains a bit about feeling guilty and having emotions he does not know how to deal with. I think the two personalities are merging a little and it bugs Red to have a softer side. Softer may fit pretty well. Mary left the drugs out indicating that she was still giving them to the MC and she also says that the MC 's dad gave here a huge supply of them that she has in her room probably locked in the dressor or maybe in the suitcase under the bed. I think it is likely that the drugs stopped working after the accident even though Mary was still slipping them into his food. coupled with the fact that the MC now calls out to red but has no memory of him before the accident indicating he never knew red was there or red was sleeping due to the drug and now that the MC is calling out to red all the time for advice and to take over maybe the drug can't work anymore because the MC is relying on Red too much?
Have you ever met someone on meds for a personality disorder (I don't know the names/terms), how they complain about feeling numb, how they want to stop the medication just so they can feel something again.Yes I noticed that, it strikes me that Red is feeling the pressure of having what is essentially 2 subconsciouses within the same head, and it's his own little mind break that's happening, When you mentioned the drugs and such and how they've been dosing the MC and how it's changed him either while taking them or after stopping them, it gave me an American Ultra vibe (Main guys real persona is locked away through some sort of manipulation)
I do think that now the MC relies on Red more often is indicative of someone who's suffering
Thats how I see Red, he has been suppressed so much that the returning sensations/emotions are overwhelming.