Grandmother want to see/ have custody of grand boys. Are there grandparents rights in Fla?

The boys father recently passed away and their mother won't respond to any phone calls nor text from me. Prior to my son's death, the mother made sure he pick them up every weekend, holuday and for their birthdays. Now that he is gone, i don't get to see them. The boys don't want to be with their mom. With the information from the boys, I feel they are being neglected.