can you replace PTO with FMLA?

Hi! A friend of mine took a couple weeks off from her non-union high stress healthcare position (I am trying to get her to quit because they are awful to her and constantly violating OSHA) and was going to spend a couple days with me. She got hurt off the clock a few days into vacation, and is now beating herself up over being on vacation when she could be on FMLA instead. Is there any way for her to push for her time to be put towards FMLA rather than PTO? She can’t even do much of what she had planned while her sprained ankle heals. We are located in Massachusetts, USA if that helps!