When she has become an "Ice Queen", most likely she's already closed her heart to her partner. She is "emotionally gone"; she has "checked out" of the relationship; she doesn't care anymore about him, or very little (or so looks like). Hence no amount of effort from him will bring back the love and warmth he craves.

Sure, he can try and improve and give his best... but from the relationships I've seen, that is usually fruitless. Once she's (emotionally) gone, she seldom comes back.

I'd say, give it a shot but prepare a "plan B" (i.e. leave her and find someone warmer than a frigid corpse ;-).