Suspension (at the very least) from the EU and NATO would be appropriate, surely? His country (where all the younger people want western lifestyles anyway and detest his government) loses all the economic benefits of being a receiving nation of EU funds, and is told that no-one will help when Russian tanks roll in - well, that should give him food for thought at least. And internal unrest on a big scale - he might have to flee to Mother Russia as other leaders who believed in Stalinism have had to.Hungary needs to be sidelined. Marginalised. Removed from core decision making.
This is an existential war, for Ukraine, and perhaps, for Russia. It may escalate. NATO cannot afford to carry a nation that has its hand on the brake. Neither can it afford the security risk of a member nation divulging classified information to the enemy.
Didn't that happen to a pro-soviet leader of Ukraine not a million years ago?