The worst case scenario ever her daughter won’t be a Queen in the future but will still live comfortably until the rest of her life, on the other hand her son’s future is ruined and he might spend time in jail!
How could you ask her to choose her daughter future role above her son’s freedom and future?
That's what she signed up for when she said yes to Haakon.
She married not only Haakon, not only a dynasty, she married Norway.
The trials are not over once Cinderella marry the prince. They are only beginning.
MM has had ten years to ponder how she'd react the day her son is caught doing something really stupid, unless she was so naive that she thought no one would ever find out. And if they did, no one would ever say anything.
On a normal human level, the parental instinct to rush to help your children is strong. But she is also the Crown Princess, she is not supposed to be normal. Normality is a luxury she can no longer allow herself.
How about her husband? Her in-laws? Her other son and her daughter? Norway?
Is it so important to try and shield Marius that all other considerations are secondary?
If the choice is between Marius and the monarchy, what will she choose? - I'm afraid I already know the answer.
As for Haakon: If the choice is between a major conflict in the family where he has to put his foot down for real or the monarchy, what will he choose?
They've had a pretty sheltered life so far. That is now over. The bill is on the table.
ADDED: Royals are indeed humans and it is not an easy situation to be in. They do however have so many more resources and options at disposal that ordinary people can only dream of.
But ordinary people also have to take agonizing decisions.
Cutting lose a child, because that child is having a severe addiction and it's destroying the family.
Leaving family members behind when fleeing, quite a few newcomers to Norway have been in that situation.
Go no contact to an abusive parent.
Handing over a severely handicapped child to an institution, because you simply can't handle it anymore.
And so on.