what year was it he and Tony went back to with the Bunker? Can't remember if it said but figure sometime in the 1960s. He stayed there after putting the tesseract back and dated Peggy and now is old in 2024 or whereever they are now. Kinda makes sense to me.

Also his other self wakes up in 2012 and does everythinng and then goes back in time at that moment so he just stayed away and watched from the sideline until then waiting I guess.