I'm talking about the Apollo Lunar Module.

You know, this bit https://en.wikipedia.org/wiki/Apollo_Lunar_Module that descended to the moon, landed, some guys walked out and grabbed some moon rocks, then they took off again and made it back to earth.

That's a rocket-propelled space vehicle gently landing tail first, and ready for immediately reuse.

Given that it clearly had been done, I doubt anyone who knew what they were talking about was telling Musk it couldn't be done.