i think his end game is still on and that ruby is working for him to get sam to use his powers and somehow bring him back

it certainly seems like it.

I've thought all along that his endgame is still in motion. Just because he's dead doesn't mean nobody else is carrying on his work (ie Lilith and/or Ruby- or Meg for that matter). Plus, the angels themselves have mentioned his endgame. If it wasn't still a concern, why would they do that?

Absolutely it's still on. Even if it just boils down to Sam, his getting stronger had to have figured into Azazel's plan, especially now that Chuck has said that everything seems to be resting on Sam's shoulders. I'm of the mind too that Ruby is helping him carry out Azazel's plan. Can't wait to see how it all turns out!