Sorry about the rant, this is important to me; I could lose my job because of this person.
My colleague can only do his work with software he is familiar with, it's like he never learned the fundamentals of what he is doing. At the start I allowed him to use what software he knew while passively trying to teach him. It worked, slowly we where making progress then suddenly our project deadline got cut by almost a year.
I am now actively trying to teach my colleague, now that it's clear that I am teaching him he is being stubborn. Several times we got into arguments with the last one ending with me shaking with fury. When I explain things to him it's like he doesn't believe me.
A few times now he has shown me Youtube videos where the youtuber does things differently, then states that I am wrong and the youtuber is correct. I would have been fine with that if the Youtube videos he keeps finding, weren't the instruction kind, you know the "Do X and Y" videos where they show how to do a thing but don't explain why there doing it.
He sits with the tutorial open next to him all the time and because what he is doing isn't the same as in the video he quickly gets stuck. I tried showing him with his own work what to do, then he started asking me how to do things that he could already do so that I would do it for him.
I tried showing him on my work, even when he can see it's working it's like he doesn't believe that I am doing things right. Often he would say a youtuber did X and Y. When I explain it's the same he just gives me a blank look.
I have tried giving him better Youtube videos, he even watched a few of them yet he still can't do the basics. He keeps going back to the instruction kind of tutorials.
I tried explaining how the software he knows is the same as the new ones. He literally told me the way substance's multiply isn't the same as Photoshop's, when I told him it's a mathematical expression and he could use his calculator to test it, he just gave me that blank look.
In our last argument it became clear that my age is a large factor and the main reason he does not trust me, he feels that because he with more experience than me doesn't know how to do a thing, then there should be no way that someone with less experience could know how to do it.