I've never had a loved one in rehab. Is it some kind of rule that you have to talk to him EVERY night? Like could you put him on with the kids and just talk to him every third night or so? I think you've got enough on your plate without an obligatory nightly phone call that clearly causes you stress and resentment (normal feelings after what you and your family have been through).
That would stress me out. Of course I'm introverted and not a phone person. Mandatory phone calls are a nightmare for me.