Somehow I seriously doubt he will sell SpaceX especially if it's just to turn a profit. Sure in case something happens and all of sudden SpaceX as a business starts flopping, he might end up selling it to other defense and aerospace manufacturers, to at least recoup some costs for whatever shareholders.
Overall I think SpaceX is his baby. Based on interviews and what i've generally read about the man, I think he's gonna stick with it for the long run. I mean hell, he wants to go to Mars as soon as possible in one of his own rockets. That's a dedicated man.