pseudokudos

An insincere congratulations offered out of social obligation to someone who has made a terribly unwise, life-altering decision. Pseudokudos usually implies keeping judgement to oneself while feigning sincerity and pretending that a wonderful thing has occurred.

A combination of 'pseudo' and 'kudos.'

"He knocked up the girl he was about to break up with. Rather than telling him what an idiot he was, I kept my opinion to myself and gave him pseudokudos on the new baby."