The first morning this happened would be the last. I would have made it very clear that this is not necessary and it is not acceptable and so how is it going to be changed now. If he could not suggest ways then I would put them forth and they would be implemented that night.
Fine if you want to have a hobby, but it should not mean an unecessary burden on your family. At all. Ever.
I despise 'snooze', but it would appear many men need it. So again, there are alarms which will vibrate under his pillow. If that is not enough he must sleep elsewhere.
I don't believe this crap about 'he is a hard sleeper'. My husband sleeps like the dead and he has an alarm like this as he now works shifts. He knows beter than to wake all of us early doors, as he says because I would not and did not do such a thing to him for years when he stayed home in the days with our daughters who are good sleepers who lie in until 7 or later and always have.
He gets up, leaves the room in the dark, does what he needs to do without waking anyone (there is only one bathroom and it is upstairs with the bedrooms and yet he's able to shower and get in his uniform without waking anyone), goes downstairs and has his cigarette, coffee and breakfast, leave without waking anyone.
And this is a flat so it's entirely possible!