Do you need a physician's referral to live in assisted living?

I am 72 years old , I live alone , no family, I have chronic depression, on medication for years, do I qualify for assisted living.

the assisted living facility did need a doctors approval and a physical exam and of course the finances

You don't need a physician's referral. What you do is visit facilities, find out what they cost, what insurance they take and that sort of thing. When you find ones that you feel will be a good fit for your BIL, tell them you are interested and they will send out a nurse to evaluate him and his needs. Once you decide on one, he will need a TB test (I've never had one not require this). And as Sunflo said, make sure to read all the information before signing. Some places include everything, and others charge for certain services and/or trips and entertainment. Almost all of them have an in-house hair salon/barber which is usually a reasonable fee.

You will have to research care facilities in your area. AL may not be appropriate depending on his needs and mental condition as you have outlined. He may need more skilled or secured care. Any residential facility will likely require a medical assessment - physical and mental before they will accept him as a resident. Usually, you fill out a a lot of forms outlining his needs, a doctor fills out their medical information and recent medical visit info and lastly, the facility will likely have their contracted nurse, etc. conduct an independent medical review, medical needs, medicines, etc.

Bottom line, you don't need a drs referral, if your brother has the money and/or insurance for long term care, he can become a resident. He will still need relevant medical information for review and as a condition of his being accepted as a resident.

Visit a few and read the fine print to understand all that is included, ala carte care costs, security, available medical services, etc. make sure the facility is appropriate for your BIL's needs.