You ask very good questions. I remember when we were going through this we had no idea what to expect and had to learn along the way. I'll tell you how it is done here and I will admit we have some very good options that many cities don't have.
Most substance abuse treatment centers will release you to either a halfway house, also called a sober house, or an intensive outpatient program (IOP). Much of it depends on your insurance or your financial situation and also on your individual situation, whether you are working and your employer requires a certain program or if you have a job and need to get back to work, etc.
The sober houses around here work in several different ways. If your inpatient treatment was extensive (60-90 days) you may be able to go into a three-quarters house where you can get a job right away, attend AA?NA meetings, group meetings, counseling, etc around your work schedule. Most often you enter a sober house where you attend meetings all day and slowly phase into looking for a job or going back to work. Twenty-one days is very short for treatment so around here you would enter the most restrictive aftercare so that treatment is uppermost and you are not thrust back into the envrionment before you are ready.
My daughter was in a substance abuse treatment center for 60 days and then entered an IOP for two months where she went to group counseling four days a week fours hours a day. She relapsed almost right after being released. She ended up in a halfway sober house where she attended meetings/counseling all day every day and was not allowed to look for a job for three months. Once she got a job she attended meetings after work and continued to have group sessions with the other house residents. She could stay in this house for as long as she needed. The cost was very reasonable, $400 a month. They cooked their own food and everyone had a job. They got many food donations from the community. Family could only visit on Sundays.
Some of the men's sober houses around here are split where you stay in the more restrictive environment for about 6 months and the move to a house with several other men and work and begin getting back into the community. It usually works on a sliding fee schedule and they do not turn anyone away if they have no funds. Again I say our city is very fortunate, with the number and variety of aftercare programs.
Most of these places are located in the city, on the fringe. There are several reasons for this, they need to be on the bus line for people who do not have cars so that you can get to meetings and work. Also the suburbs do not want these centers in their area and it is too expensive to locate there. It's a shame because I have never known any problems to come from any of these places and in fact the residents are very community minded and give back in many ways both in services and support.
One of the philosophies of treatment is that you give back, so that when members are in recovery for a certain amount of time and they have their own car, they are encouraged to drive other residents to meetings and to help those just coming into recovery. I can tell you that the support they give each other is unlike anything I have ever seen.
I would not be concerned about the area the center is in, they take care of each other and I would trust your cousin.
If you have any other questions I would be happy to try and answer them.