Yahweh exists. Allah does not. Simple. The attempts to commingle Yahweh and Allah to become an all inclusive one g-d for both religions is ludicrous.
To a Muslim, Allah is not their Heavenly Father, but man's slave-master. Allah is not about truth but is the deceiver of the infidel. Allah's kingdom IS of this world whereas Yahweh's is not.
I could go on but I think you get the picture. Allah exists... we just know him by his older name.