I'm sorry when I looked at her things, I realized I might not have been clear that you might need to have one chart for an hour, so the minutes can be clear...not all 12 hours on one chart.

Everything would be tallied up for one "session" (this time being maybe from the time he gets home in the afternoon until bedtime for one day?) and have him fill it in when all is tallied. If he is too tired you could start by having him fill in the previous day's data before he gets started on his current day homework.

If you have a white board or chalk board you could "reuse" the space but at first it's good to start collecting the charts on paper over a period of a week or so and your DS can analyze what has taken plac. I'm assuming he probably likes to analyze data like my DD.