IPL season, a grandfather who lives with us, a 12 year old, and one TV

My father has watched every match for years. This season our daughter has picked the opposing team, mainly to annoy him, and now the two of them watch together till the last ball. Night games finish close to midnight. Our house wakes at 6.30 regardless, because my theatre days start early, and she is wrecked by Thursday. I'm the one who has to be the bad guy. Do you set a cut-off for night matches, or let it go because it's the one thing they do together every evening?