One cat sick the other is not

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I don't know what to do. My male hasn't been able to hold down anything all day. He's lost all food and is throwing up bile even because there's nothing else. My vet is closed due to pandemic. He's acting fine, still cuddly, seems happy, maybe more tired than usual but that's it. My female is doing just fine, no puking same old attitude, eating great. I just dont know what to do with my male, it isn't like him to be vomiting like this. There is an emergency only vet open but they charge hundreds of dollars just to get in and my SO and I are both out of work due to the pandemic so its really a last resort. Anyone have any suggestions to help my baby?