"is gone" implies a status; "has gone" implies an action. "is gone" = he is no longer here, and often implies that he is not coming back. "By the time the police arrived, the burglar was gone." {Note: to imply that he is not here but is coming back sometime, use "away": "He is not in the office because he is away on business.") "has gone" = he went somewhere. It does not imply that he is not coming. "My husband has gone to New York on vacation, and will be back next week."

Maybe "Is gone" is an actual state, and "has gone" refers to the action to become "gone". I'm not a teacher, but, it's my feeling. 😁 The "has gone" is some kind of present perfect, some that started in the past but still happen.