Is the word 'real' synonymous with 'exists' in Buddhist doctrine?
In the conventional truth, mirages exist and are real as a mirage but not real as water. Dreams exist and are real as dream but not as a play in a theater.
So there is nothing which can be said conventionally existing but unreal because it is real in that way it is called to exist.
Conventionally existent Buddhas alleviate the conventionally existing suffering of conventionally existent sentient beings.
The suffering sentient beings are conventionally existent and are also conventionally real.
Conventionally existent Buddhas however don't alleviate the conventionally unreal and nonexistent suffering of the son of a barren woman.
I think this answer by @Tenzin Dorje to a related question may be relevant too.