Hi and welcome to Talking Point. I am not sure but think the behavioural support unit you mention is what we in The UK call an assessment unit. It is where medication and behaviour are monitored, help given to the patient and the best form of care in the future decided.
My husband was in an assessment unit for 9 weeks and his care going forward was in a nursing home for dementia with challenging behaviour.
Not sure my thinking is right but I am sure someone on the site will know.