Based on what I know of him, I'd say ISFP 4w3. I think he had unhealthy Fi that is especially evident in his manifesto, he didn't feel like a failure because he couldn't fit into the social mold of the world around him but because the world wouldn't fit into his ideals of what should be valued. If you look into his past he actually never even tried to approach women, he expected them to offer themselves to him and felt rejected when they wouldn't do so. He carried the same mentality towards everything else in his life, he even once demanded that his mother marry a wealthy man and got upset when she didn't do so for him. He drowned in his emotions constantly, explaining in vivid detail his emotional agony and feelings when things didn't go his way or people didn't accommodate him, it was always entirely based around himself and never extroverted behavior. He never felt the Fe need to meet the societal standards around him or accommodate for other people so that they would actually enjoy being around him, the very idea of changing for others disgusted him. He wanted the world to serve him and his social ineptness. Despite his narcissism and narrow-mindedness, he was always very attached to how he felt, so attached that he valued it above what anyone else ever did. Half of his manifesto is just him talking about his feelings and justifying why he did what he did by showing off how unfair people had been to him. He was very unhealthy Fi, completely enraptured in himself and his values, extremely emotional yet utterly devoid of empathy for other people.
He was also very materialistic and concerned with physical beauty in a way that I don't think inferior Se is. He attached himself and his self-worth to the things he owned as a reason for why he was above other people, he was constantly talking about how beautiful he found himself as well as cursing his mother for being Asian and giving him non-Caucasian physical qualities. He felt materialism was something that set him apart from others as well as held him back, it was a primary part of his worldview, not just an inferior function lashing out.
It's worth noting that he was very different in his videos than he was in real life, he was most definitely trying to make himself look far more confident and socially dominant than he really was (he freely advertised these videos on online forums and showed them off, despite his insecurities). In real life, people said that he acted entirely different, was usually very quiet, oblivious to the discomfort of those around him and would inappropriately express his less than positive opinions on women as well as come across as sluggish and pathetic. His videos are a good look into how he viewed himself but not the way he behaved on a regular basis.