Can I sue my sister for holding up moms guardianship proceedings by ignoring all correspondence?

I applied for guardianship of our mom and at the hearing my sister wanted to have joint guardianship, which started a fight she lives in Fla I live in the same town as mom. We decided to have her be dads and me be moms, I wasn't happy but my lawyer said we can try to change it later, only because mom had to be placed. There was a stipulation that she had her lawyer draw up, that needed to be signed to have the judge sign the guardianship papers for me. In the mean time my sister prevented me from moving my dad and mom to a joined facility to be together and to get dad closer to us (he was 21/4 hours away)this new place would have been 20min. away. My sister is ignoring all calls(she changed her #'s) won't answer letters and when our father died I had to get her signature for permission to cremate him, she only would speak through her daughter to me. Mom is being miss treated in the facility she is in my hands are tied I can't move her without a guardianship paper, my sister knows mom isn't getting the best care but doesn't know the full details. It has been almost a year since this all started and my lawyer is NO help at all, any advice for me to get her to tell the court she wants nothing to do with mom. I have a post card from her she sent me after we went to court where she said I would regret doing this to her (not having joint guardianship) and that she didn't want to know if mom got sick or when she died. Mom never did anything to hurt her ever she is the sweetest person around always was, and still is. I don't know why my sister is doing this. Please help