Knowing Alfie had betrayed him, Tommy traced him to Margate, confronting him on a beach. Alfie revealed that he was suffering from skin cancer; he had intended for Tommy to discover his betrayal, track him down, and kill him so Alfie could die on his own terms, rather than the Mafia.

Is Alfie Solomons good or bad?

12 Alfie Solomons

He has no trouble manipulating others, including Thomas, as long as it gets him what he wants. He's even willing to let others die for his needs. Though he's technically a good guy by the end of season 5, he's not a good person at his core.

Why did Alfie Solomons betray Tommy in Season 3?

Tommy would have allowed him to live. THIS. He betrayed Tommy for the same reason he pretended he knew about his son's kidnapping. Its the same lesson hes making to tommy and since hes got the cancer he may as well die doing so.