Soft restraints are not intended to keep a pt in bed; they are there to keep a pt from interfering with medical equipment. (one of my first shifts at my current job, I got into an argument with the charge nurse because she wanted me to put a pt in restraints bc she was getting out of bed, but I refused. To me, there was more potential for injury with the restraints, given that she could physically get out of bed but was very confused than there would be with the bed alarm and everyone aware of the situation- she was already next to the nurses station) I am not a fan of them and would much rather have a pt in mittens, to keep them from pulling things out, but not have them tied down in any way. If the pt is a fall risk, interventions are a bed alarm, increased rounding, room closer to the nurses station, ensuring the pt has what he needs within reach, frequent toileting, etc- not restraints. I have seen an enclosed bed used with a TBI pt in a rehab setting before, but I am not totally familiar with them; personally I would try a bed alarm first. You said the pt was standing in the doorway, not that he fell out of the bed, so the tent doesn't make a lot of sense to me.
As far as removing the restraints, I would agree with what you did. If the pt is compliant and was not pulling at lines during an entire shift, where would the justification be to keep them in restraints. We have to document every 2 hours when we have pts in restraints (I work m/s), and we have to put why we still have them on.