Exactly - sugar coating, protecting him, although your planned result (his awakening to his problem and solving it with your help) did not happen at all.
His MIL sugar coating his behaviour is the same thing, her desired result may be different (she just wants to think of her Son as having a somewhat productive and "normal" life) the intent from both of you is the same.
You will both "save" him, show him, teach him, rescue him, make him look "ok".
He, on the other hand, just drinks.