Can Someone Who Works or Worked at a Hospital Help Answer a Question About Drug Detoxing?

My boyfriend is a heroin addict. He finally is ready to get help. He had a scare when he had to go to the ER last week and they told him that his kidneys are starting to fail and if he doesn’t quit, he’ll die. I helped get him into a drug detox and rehab center for those without insurance and no money but they won’t have a bed open for another 5 days. At the detox, they will give him some meds. so the detoxing won’t be so awful. The problem is that he has to wait 5 days and we (his family and I) don’t want him using in the meantime but he is so “dope sick” that he needs something to help with the withdrawl. I called our local hospital and they have a floor that they use for detoxing (a mental health floor) and they have to admit him. My question is if they would give him ANYTHING to help with the suffering this withdrawl causes? And even if he does detox there, don’t you think he should still go to the rehab especially since it’s free? Thanks for any advice.