The correct phrase in this context is: 2. He is on charge. Explanation: * The phrase "on charge" means someone is responsible for something or in control of a situation. * This usage is informal but common in spoken English, especially in certain dialects. Examples: * "He is on charge of the project." * "She is on charge of the team." In your example dialogue: A: Why don't you do that? B: He is on charge. This means that "He" is currently in charge or responsible for whatever "that" refers to. Note: * "He is in charge" is the standard and formal way to say someone is responsible or in control. * "He is on the charge" and "He is in the charge" are not correct phrases in English. So, based on your context and the native speaker's usage in the movie, "He is on charge" is the correct expression in informal spoken English.

All are good grammatical sentences. Only #1 is commonly used. I don't know how the other three could be used or what they might mean, but it is possible to find special situations where they would have a useful meaning.

'He is in charge' is correct. A battery is on charge, so perhaps you heard incorrectly. Billable expenses can also mean the customer is on charge. Depends what the movie was about.