You're very welcome. It is hard growing up in this day and age.
As for being wishy washy, I was beaten/brought up by a very old school military father and I in turn served in the military for a couple of decades. I was brought up very old school, but over time have grown up and realised that my beliefs were not accurate and not helpful. Hopefully your DH will too.
However, if not, registering for something like DBT would be great. I have had a long wait but knowing that I was in a waiting list helped (and I had access to CRISIS support while I waited). The course I am doing is emotional regulation and is basically DBT. It is 5 sessions with a lot of practical stuff in between.
Week 1: Mindfulness . How emotions, feelings, actions and thoughts are linked and how you can break the link. Square breathing (I prefer breathing at 4 second in breath and 6 second out breath). Non judgementalism (I'm terrible at this)
Week 2: Changing your body chemistry - Using cold water to calm yourself. Progressive muscle relaxation. Improving sleep. 20 minutes exercise a day
Week 3: How to prevent acting on Unwanted emotions - Stress. The stress bucket. STOP (Stop, Take a breath back, Observe, Proceed Mindfully)
Week 4: Check the Facts - Looking at emotions, thoughts and actions and how one triggers the other. Unhelpful Thinking Styles (mental filtering, jumping to conclusions, labelling, emotional reasoning, catastrophising, personalisation, magnification and minimisation, black and white thinking). Wise Mind,
Week 5: ABC Please - reducing vulnerability to emotion mind, accumulating positive emotions, (short term and long term). Mindfulness of pleasant events calendar. Gratitude Journal Prompts. Helpful Apps. Helpful Websites
These sessions in my case are 2 to 3 weeks apart to let you practice them and see how they help.
The helpful apps are basically mindfulness apps. Personally, I would recommend Smiling Mind (free and has a very good few introduction course), Balance (which is a new one and free for a year at the moment) and when you get a good handle on it Insight Timer which is all you will ever need (1,000's of free meditations but it can be overwhelming for new people). I've studied a lot with mindfulness (there are some great courses around including free ones with Future Learn (Monash University)) and have introduced it to my daughters to help them with some of the problems they experience. I would strongly recommend it. They are both finding it very useful. You can also look at online mindfulness based stress reduction courses (I did an 8 week one which I found terrific).
The above will help your daughter to become the grown up in the arguments and it will help her emotional wellbeing and mental resilience.
Aside from that there are lots of self help books out there that she can look at (I've bought my daughters a few) and there are lots of free courses out there and helpful websites like mind.org.uk and anxiety.org.uk
As for fluoxetine, you can look it up online. I took it in the past, but unfortunately for me the side effects were bad as I tend to be sensitive to pills.