I really cannot accept that there is anything in the way the guy sings or plays that suggests he wrote the song. I fear you are projecting your own thoughts on to what seems, on the surface, a perfectly straightforward rendition of the song.
If I wished to be philosophical about it, I would say that I look for a singer to seem as if he or she owns the song that they are singing. That is not the same as seeming to have written it.
In my field of interest, it is well-known that, while Dylan wrote "All Along The Warchtower", Jimi Hendrix did a version that became more well-known. I can remember, in 1981, being in Mannheim for a Dylan concert. The venue had changed from an outside stadium to the Eisstadion. I went with a German friend, who stood on one side of me, with two young Americans, soldiers on leave, on the other. When Dylan played "Watchtower", one said to the other, "Hey, he's playing a Hendrix song". He probably added "Far out!" or something similar. When I pointed out that Dylan had written the song, the one nearer to me asked, "Really?". On being told that this was so, he said "Wow!" and told his friend. Dylan had adopted and adapted the Hendrix version for his own live shows. Dylan may have written the song but Hendrix "owned" and Dylan had responded to that.
The guy in that video sang it competently but there is no way that he "owned" the song.