House Lien Advice/Help please.
	
	
		I don't know if this is the right place to post this, or If I can even find the right forum to get some advice, I will post my current situation in a few places and will check them all. Please Read
I will try to be brief
Current Situation : I'm a son trying to help out my dad with some information, my mom passed in 2001 so now I live with my dad. A few months ago a company came by and wants to buy every house on my street. Which is very lucky for anyone on this street. Me and my dad have a sale pending on a very nice house not too far from here. However just the other day my dad ran into a sticky situation. He got a call from his laywer, finding out that there was a lien put against the house. The lien is from my mom, when they divorced in 1992 my dad never knew anything about this lien ever, there was never a co-sign or anything. My mom had her name on the title, the papers were signed 6 days before she signed separation papers stating that no one would collect eachothers debts if any. 
If this lien gets placed on my dad, he may not be able to pay for it and we are screwed, completely.
Could someone in the state of divorce create a lien against the house without knowledge or consent of the deed owner?
What options does my dad have to remove this lien.
I hope I made sense, I only know so much. I can post more information within time, I hope that someone replies who knows a thing or two about house liens.
If anyone can help me, thank you