how old is your brother?
the alcoholism is not acceptable and should not be accepted under any circumstances. NAMI, the national alliance on Mental illness in the U.S. hosts family support meetings you could go to to get even more suggestions about dealing with your brother. dial (800) 950-NAMI (6264) to find the name and number of the local NAMI chapter in your city or town.
Regret I would suggest he needs to live in a group home. NAMI advocates draw the line at drinking or street drug use in a family member's home by a loved one with a mental illness.
Is he taking his psychiatric medication or self-medicating with the alcohol?
Your immediate concern would seem to me that his symptoms are not under control yet. Getting his symptoms under control would allow your brother to help you care for your elderly father. Unless his symptoms are under control, he will not be productive at much of anything at the rate he's going.
So: I would not concern yourself with having your brother help you care for your father. The goal to me would seem to be that your brother needs to get treated for his schizophrenia by a doctor who is willing to try every drug necessary in order to find the one that gives your brother symptom relief.
Because: from what you describe, he is either not taking any medication, or the medication he is taking is not effective and he needs to try another one.
He might also lack the awareness that he is sick (this is a symptom called anosognosia). If he has anosognosia, it will be difficult for you to convince him to see a doctor.
I'm going to end this by restating that he needs to get his symptoms under control before you will be able to have help with your father.
If you can make or exaggerate the case that he is going to be a danger to your father and is already a danger to you, you might be able to get your brother committed to a hospital for immediate attention for the symptoms of his illness.