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The first thing you need to do is establish the FACTS. You have given us her side of the story, we do not know their side. A material lie makes nonsense of any recourse you have. They typically document all that went on and provided her some paperwork to sign.
On the surface, it appears they have grounds to refuse her entry since she did not have proof of her return. She also did not have the supporting documents for her visa. These requirements are pretty standard.
Now IF you establish that she did not lie, I recommend you file an appeal. This is because a deportation in your immigration history will follow you around even when applying to other countries, unless it is addressed. You have little to lose by appealing, worst case you get denied again. If you're lucky, you get approved and clear that black mark. Additionally I believe she still needs the medical treatment she was coming for, so an appeal is in order.
A deportation is a serious immigration event and with the scenario you described, your best course of action is to retain an experienced immigration attorney.
How to appeal a refused Schengen visa?
A deportation is not like an ordinary visa refusal which one typically can appeal by oneself. Expertise is required in such matters which you likely do not possess.
Concerning the pictures, humiliation/torture and filing a complaint, once again an attorney is the best person to evaluate the case in it's entirety and offer advice. Note however there is a high bar to overcome to win such cases. They have rights to collect her information and question her although not to abuse.