He's upset with you because he forgot his stethoscope.? This is disturbing! If he can't remember to bring basic equipment with him, should I have trust that me won't "forget" some other pivotal to my health or life?
You may not need an attorney to receive child support. Contact your local social services to see if they will help before you fork out money you don't have. Congratulations for dropping that tool. He's a jerk.
I am conflicted. She doesn't seem to want material/monetary support based on the post. She is needing emotional and mental support. If you love her as family, then you should love her now when she realizes her mistake. Kindness hurts no one. We are all flawed and sometimes let hormones/emotions over power reason. Praise her for realizing what a tool he is.
You said this is not the first time. Are her injuries/emergencies verifiable? If so, YTJ. If not, is she intentionally wrecking your time together? You both need to have better communication. And, lastly, if he is a good man, you will never be more important than his children. Get used to it.