A unit in this case refers to a large individual in particular a male. Fried usually refering to the brain being fried from copping one too many rompers. Combined you get a big cunt who has lost almost all his capabilities to perform the simplest human functions.
Drew: oi Greg this party’s getting out of hand there’s too many fried units here.
Greg: Ye bro and did you see that bloke Baz he’s so fucked up he forgot his name.
Drew: what a fried unit!!