Im siding with puma, paranoid schiz, w/ sudden onset I'd add.
Since we only know what his parents have said about him, theres no ruling out hallucinations/hearing voices.
Eating flies sounds more of a delusion than disorganisation.
Sleeping by his mothers bed-side sounds like an odd-belief.
He also has poor insight into his own condition.
Triggering events such as his mothers death, and a family history of substance abuse.
He lacks close friends by the sound of it.
When he spoke he sounded paranoid, afraid.
Although I dont know what schizophreniform disorder is, I would rule out schizotypal and schizoaffective.
I was about to study psychology at university too, but dropped out due to paranoia. Im just wondering, how are you finding it? Is it interesting?