Ok...you have been in FL for two years. Get an attorney in NY and ask the attorney to challenge jurisdiction based on the fact that dad is incarcerated and you have lived in FL for two years. Get the attorney to challenge jurisdiction based on "inconvenient forum".
Has anything at all happened lately that dad could have evidence on to show you as unfit? Or that something dangerous has been going on in your life? The court cannot take custody away from a parent, and give it to a third party, without due process.
However, if you don't properly respond and challenge his case, he could win by default, no matter how wild and crazy his accusations might be.