Do you have proof of that?
Well, what kind of proof are you looking for? I mean, there is loads of documentation that his body was flown back to DC that same day and autopsied at Bethesda Naval Hospital, but, when it comes to anything with the JFK assassination, some people won’t accept any kind of proof that refutes their pet theory.
So, I could post the testimony of the doctors that autopsied him, the autopsy notes, the autopsy photos, etc. If that stuff won’t satisfy you, though, then I won’t bother.