I did research this and found nothing. Someone asks you an honest question but your answer is an insult.
For starters, or to start with Luther’s “end”, Luther apparently killed himself.
https://damselofthefaith.wordpress.com/2016/12/07/did-luther-commit-suicide/
And for a compendium of Luther’s obvious insanity and reprobation, which included blasphemy, check out the following:
https://www.barnhardt.biz/2016/01/26/luther-in-his-own-wordsoct-2017/
Sorry if what I said gave offense. As you suggest, I may be wrong, and it may be objectively difficult to separate the wheat from the chaff when it comes to certain historical figures. If left to his own devices, Bergoglio would probably rush to try to somehow canonize Martin Luther as a saint, despite his not being Catholic, and despite the wealth of countervailing information available to diligent researchers.