The difference, of course, being that there are no written accounts of Crocket dying of typhoid, nor are there any written accounts of him being killed by invisible aliens. There are accounts of him being executed after the battle, and there are accounts of his dying during the battle. Since you weren't there then there is no way you can pronounce one version to be true and the other to be false. Unless, of course, the aliens told you.
Fiction has been known to write stranger things and there certainly are plenty of historical fiction accounts out there. But considering that YOU rejected the one account suggesting his execution, along with any other, when asserting that they were equally possible, so it must also be for the others I wrote of.
There are accounts of him being executed after the battle
Correction: there is one account reportedly written by a Mexican officer after the battle. That alleged account has no credible history of its location or existence prior to circa 1965 and is believed by many with strong evidence to be a forgery (the pages are loose and unbound, of different paper composition, and appear to have been cut into a uniform size suggesting it was written in succession and at the same time on collected blank scraps of 1830's era paper gathered from different sources). It is only slightly more credible than a work of fiction if even that. But since you yourself previously rejected its credibility along with all other accounts, you cannot attempt to reinstate it now that it has been pointed out through statistical probability that what you declared, viz.: different means his death are equally possible, is in error.
Since you weren't there then there is no way you can pronounce one version to be true and the other to be false.
No, and neither you or eye can ever conclusively prove that invisible aliens didn't kill him for that matter since no explicit and credible record of his death exists. I can conclude statistically that some theories have a substantially greater liklihood than others, and that some possible ways he could have died - such as the aliens - are so far fetched as to render them statistically improbable to degrees of less than than one in multi-billions.