It is not at all surprising that kids there would be using profanity, but foul language or disrespectful behavior of any kind, directed at either residents (patients) or their families is absolutely out of line. That having been said, I do not know what kind of facility your AD is in, and that will certainly make a great deal of difference. If it is a private facility for which you (or insurance) is paying good money, then this behavior is totally inexcusable and you should take it up with management. If however it is a state run or a charity facility then I can understand that the standards would be lower in which case I am not sure there is much you can do.
I do not want to make any presumptions but I will tell you this much - there are a lot of rehabs out there where the staff themselves either are not clean/sober at all or have very little time, and so more often than not the staff have their own issues in addition to those of the residents. In extreme examples there have even been cases of staff in rehabs selling narcotics to residents. I am not implying that the facility that your AD is at is like that, but I am saying that you should not assume that the place is run to the highest standards just because one of their staff members is bragging about a "success rate."
There is no question that the staff at a rehab want to be "hard" on the residents, but that very rarely should involve any kind of duress, intimidation, foul language, and of course never the threat of violence. Being "hard" means calling the A on their disease, their attempts at manipulation, their denial, etc., etc., and does not involve staff practicing those same behaviors themselves.