The phrase Till he came correctly answers the question about the duration or end point of an action. It specifies that the waiting ended upon his arrival.

১. Till lunch time is a valid phrase but lacks the specific past action context.
২. Until 6 O’clock refers to a time point rather than a dependent event.
৩. Since this morning is a response for questions starting with Since when.

অতিরিক্ত তথ্য: Till and Until are often interchangeable in informal contexts to mean up to.