Yes, just what the person before said, and he was registered in a forum, for vegan recipes, or in general for vegans/vegetarians, as long as I know. He was 112 pounds while the shooting, so 51kg and 6ft tall, so 112 pounds on 6ft, which is severely underweight.
edit: And as you said, you want to know to what extent he was underweight, he was so strongly underweight, that he easily could have brain damages a long time already, and he PROBABLY had already, at the time of the shooting.