Question about permanant, non-modifyable alimony in Florida... is it really permanent?

My dad and my mom have been divorced for seven years now. When they filed for divorce, my dad couldn't afford an attorney and kinda got screwed -- divorce is a hard thing on people and during the stress of it all, it was accidentally overlooked that my mom was requesting alimony pretty much until the day she pes on, or gets remarried. My dad is living paycheck to paycheck and the extra money he's having to give her is killing him. Well, my grandmother (my mother's mother) ped on last May and left my mom over $100,000. Now it seems that my mother is continuing to say that she "needs" that alimony money because she's being spiteful and thinks my dad ruined her life, yadda yadda. In the divorce decree, it says that it is permanent, unmodifiable alimony. My dad is hoping that if he writes a letter asking her if she would stop it that she will, now that she has her inheritance money. My question is, can SHE modify it, or is it only HIM that can't modify it? Has anyone been through a similar situation with permanent, unmodifiable alimony in Florida? My dad's attempted to talk to an attorney, but they all seem to want money before they give him any answers. Also, if anyone knows any male family law lawyers in Orlando that could help, that would be fantastic. Thank you so much for your help.