What does having a neice on a full ride d-3 scholarship have to do with anything? The laywer/parent is a joke and in my opinion the girl should be playing with the girls.. that is why there are girl teams.
Hmm... Sounds like you might be surprised if you played catch with my daughter. She was just clocked throwing a softball overhand at 68 mph. She is also a D-1 committed Big-12 recruit in her junior year of high school.
Some young ladies are very competitive in traditional male sports. Some are not. Weather she is allowed to remain on a team should be the coach's decision. If the parent that was complaining about her being on the team is not happy, take his kid and and his goat smelling butt to another team.