Prepping for mediation and possible trial?

( not sure if it matters but child in this is 9 years old and has been expressing since her parents split she is happiest with her dad)
My fiance has mediation next month for his daughter, his ex filed custody papers to get full custody because the child told the ex that she is happier with us and wishes she could live with us. Ex has said as long as my fiance will agree to reduced hours every other weekend, more child support and no holidays, birthdays, or track outs than all can be settled, otherwise it goes to trial. The ex does not have a lawyer, nor do we, so of course we are very nervous about all of this. If we do have to go to trial what all would we need to prepare in our defense and why we feel as thought the child is better off with us? We are very concerned because his ex has a violent temper and the child on several occasions has watched the ex physically attack or take a swing at other members of the household and it really scares the child…is that something we could use to help fight for her?

Your post is very broad, and discussing specific trial strategies and mediation preparation on such a large scale is outside of the scope of this forum. You should consider using a consultation to discuss with an attorney in your area how to present evidence and what issues you should make sure you cover in your testimony. You could also consider using Rosen Online. This is a monthly subscription service we offer where you can ask pointed questions about your situation and obtain assistance with preparation and/or settlement of the custody issue.