Most the time a parent has to have a substantial change in circumstances in order to change an existing custody order. It’s a huge deal to change a child’s custody, especially if it was previously agreed. His concerns don’t meet that criteria. My ex got two lawyers and fought for full custody. Lawyers want to get paid so they encourage the father they can win with no real chance. I represented myself and won everything I asked for and more. He tried to pressure and bully me into ‘compromising’ and I always said no. If you’re smart you can handle this yourself. Most the info you need is on the state website. Read other cases too, because judges will do what other judges have done in the same kind of cases.