No one can answer whether or not you can win. Speak with an attorney, give them the property address and discuss how she was able to do this. If...

You cannot. You gifted him an interest in the property and you cannot take it back. The only way is for him to cooperate.

No. They have filed a responsive pleading so the court has jurisdiction. Just serve and file a POS of the Amended Complaint.

Take your proof to small claims court and sue him.

As long as your last payment was more than 4 years ago, they cannot sue on this debt based on the facts you provide.

Continuances are usually liberally granted by courts.

Possibly. The court would need to have jurisdiction over the matter.

Speak with an attorney and provide them your grandmother's name. They can do some research and assist you with making any claims.

Not likely since you have not been served and therefore don’t know what you can and cannot do. For instance, does the order say you physically...

If your mother had capacity and did that willingly, it is legal. If your sister used her power of attorney to purchase the property, then she...