Lis Pendens/Quit Claim/Effect on Credit

our attorney advised us to check to see if our credit can be negatively impacted before we proceed with her response to lis pendens/civil summons. husband put up 10% downpayment on investment condo in naples fl with his son's fiancee in 2005. he is not on the note and is on deed with her. we were served 03/04/09 with lis pendens (me as "unannamed spouse" since he is on mortgage). son and she now married and efualted on payment july 2008 (attempting a short sale and advised to do that by some realtor). should husband do a quit claim deed? can we be liable for any deficiency decree that may occur? (mortgage is $316,000;short sale offer (ignored by bank) for $70,000).we are willing to walk away (never see the 10% silent partner investment) and know he will not see profit from this. daughter-in-law and son are basically ignoring this and hoping it all goes away. she is only one on note. husband and i must protect ourselves. what is best course of action? can this negatively impact his/my/our credit? thanks to all reponders!