The Pill taking subplot

Because he’s considered a senior citizen you DOPE

You know, high cholesterol, blood pressure etc etc etc

Did you eat lead paint chips your whole life??? Good God

I think they were some sort of mood stabilizers. That’s why, after things started to get serious, he tossed them in order to get his “normal self” back.

Ummmm because he's old and did you see the shit he went through in the other movies?

Who knows? I'm guessing they were antidepressants, or anti-anxiety, or something like that, because first he was popping them like candy then he just dumped them out. If they were essential for treating some medical condition he wouldn't have done either of those things. It seems like he wanted to let loose his full inner rage, flashbacks and other assorted PTSD stuff be damned, that's why he got rid of the medication. No chill pills for old man Rambo today!

Helps him control the crazy.

to avoid turning into Rambo-Hulk