Workaholicism as you describe it is a pattern. It can only be broken from the outside, or by health crisis. The pattern is not the person.
I'm fortunate to live in a part of the country where it is still considered part of the spouse's job description to see to their loved one's health. The ladies here trained me well, but the husbands do it for their wives, too.
Another (the Bishop's wife) one smiles and does it this way. "Honey, I've booked us tickets for [insert event]." PERIOD! She gives him enough lead time to make the workplace arrangement he needs to make, and there is no discussion.
The workaholic thing is a pattern that cannot be reasoned with and can only be interrupted or accommodated. I had to do that with Hardi a long time ago. He thanked me for it, once he'd finished sleeping, and has been cooperative with my "strategies" ever since.
It can start with a one-day revolution where you turn off the alarm (or reset all the clocks), call him in sick, and then proudly tell him you did it, once he gets up. It isn't until he's had some down time that he can get some perspective on what he's been doing to himself (first) and those he lives with (second) and those he works with (last).
If you liken it to an illness, which it is, would you want a loved one to stand by and let you plunge a knife into YOUR heart because "it's up to you"?
Workaholicism as you describe it is a pattern. It can only be broken from the outside, or by health crisis. The pattern is not the person.