I’m no legal expert, but I’m pretty sure this Doc doesn’t want to make a big deal about this. If this is widely publicized his business is ruined! Who would trust someone to do work on their beloved prized organ again, when there is even a hint of something like this happening and then an attempt to bully and silence afterwards?
Either you can provide the service you advertise or you can’t and this guy may be in breach of contract and the OP may be entitled to compensation. There are plenty of no win no fee lawyer firms in my country that would be rubbing their hands together at some wealthy medical practice in this position.
I’m pretty sure Thunders Place isn’t liable for what members post, as I’m pretty sure it states when you sign up you are responsible for what you post.
I might consider a counter offer of asking specifically what part of the product review is defamatory and the possibility of making alterations to that should there be a legal requirement.
The asking for members personal information part, is this a request? Or is there an actual legal document ordering/requiring it? The terminology is important I believe and I think they will need to comply with the laws where your servers are hosted in order to legally gain access to the information they desire. Hosted in Cuba isn’t it?
Also as a doctor (not me), I’m pretty sure this guy should have a healthy respect for patient confidentiality. It seems somewhat unethical to ask for this information, but surely the Doc knows out of all of his patients which one is upset with his service and already has this members personal information, or is this not the first time something like this has happened?