Pawned house and lot

My grandma and aunt decided to pawn the house and lot. The problem is that the house and lot is named to my dad, uncle, and my aunt (who pawned the house and lot). My grandma and aunt did not tell my dad and uncle that they pawned the house and lot and they just found out recently because the house is being foreclosed and they got a notice for the foreclosure. Someone told my dad and uncle that they could file an adverse claim, because they both own the house and lot and didn't know about it being pawned.

What has to be done for the adverse claim?

Would my grandma and aunt be sued by the lender?

Will the adverse claim stop the foreclosure of the house and lot indefinitely?

hello po atty. heres my story: lot title name by my mother at taga pagmana po ay father ko at we 4 siblings. now my mom died already. then after my mothers wake, we siblings dont know that my dad pawn the lot title to his friend which is still named by my mother.
just recently my dad also died then my dads friend came to us asking kung when namin pweding bayaran yung title na nakasanla sa kanila (which we dont know na nakasanla pala).

my question po:
1. whats the best thing to do about it?
2. pwede po bang angkinin nila yung lupa ng mother ko if nd namin sila babayaran?
3. is it legal po ang pagkasanla if we siblings dont know and no SPA for my dad from us?

hope matulongan moko kung anong gagawin ko po sa problema namin. maraming salamat po at GOd Bless po...