What is the cause of this person's rapid weight-loss?

I'm a college student, and there's this one guy who's been in at least one of my classes every semester I've been there. I always wondered if he had cancer or some kind of illness, because he's only about 20 and is almost completely bald. He has like the hair you'd find on a baby/toddler (very thin). Last time I saw him was late May, just before summer break. Classes began today, and the kid looks COMPLETELY emaciated, like you can see every bone in his body. And his eyes are sunken. He's a walking skeleton and literally looks like he just went to hell and back. But yet, he's there in class and acts fine and everything. Keep in mind that this guy was probably 170 or more lbs by my estimate in late May. In fact, he might have even been a little overweight. Now I swear he's more like 110. What would cause a person to lose 60 lbs over a summer? Parasite? Lupus? Chemo-therapy? Medication of some sort?What is the cause of this person's rapid weight-loss?
Cancer for the weight loss.


Chemo for the hair loss.





Don't be a stare bear, go up and ask him.What is the cause of this person's rapid weight-loss?
I think its the T-Virus, does he wander around looking to feast on human flesh?