Yes. It is immoral to create a fake photo of an historical person.
History is about facts. This is fiction. This is a hoax, a fraud, and should be immediately destroyed and removed from the internet. Removed from this site.
Historians are in a war every day to prevent lies from being established on the internet as 'truth'. AI generates lies that are difficult for the common person to distinguish from the truth. The very existence of this fake image on this site has already been absorbed by the search engines as 'fact'. But its a lie, a fraud, a hoax. It degrades the very nature of the world we live in by filling it with more lies. We have enough politicians and trolls trying to do this already...
So yes, creating a fraudulent image passing it off as a historical person is immoral.
(I can not speak to the accuracy of this image or its utility as a possible 'artists impression' since we have no information concerning the tools used to create it.)
Images generated by AI art are fascinating, and can be quite interesting, but the result is completely based on the model being used and the prompt being fed into that model. It in no way will perform any reasoning, thought, or artistry to create an image, it is merely a reorganization of material it has viewed during the AI models training process. Note the two watch chains on this image-it copied from two existing images somewhere, each of which had a watch chain in different locations, so without proper negative prompting it generated two watch chains in this image. This reiterates the copycat nature of this tool.
As I stated above, the danger here is that this image, like many AI generated answers, looks close enough to be considered valid. In these days of web scrapers gathering information, search engines fighting to introduce AIs which not only perform searches, but try to present answers to queries placed in their search bar, it is inevitable that, even if the OP clearly states the image is not real, it will be taken out of context and presented as fact by a search engine somewhere, and someone will believe it.
(As a side note, I will point out that I am not speaking from complete ignorance. I have 'tinkered' with AI art generation for in excess of 100 hours, generated hundreds of images, so have at least a basic understanding (I hope) of the processes involved.)