To the OP, it is always good to be concerned dealing with any large money matters that occur in Thailand.
1. How many fathers DO NOT KNOW where their daughters are? Very, very strange. Father claims not to know where she is, yet she signed a POA? I would want to know the Australian father's personal finances? Perhaps he is broke and selling his daughters land unbeknownced to her to he can have the money stay in Thailand? Where is the daughters mother in all this?
2. Can any poster verify 100% FACT what happens after the sale if the POA signature is found to be forged by the father? The daughter claims she did not sign it? How did she sign it in the first place if no one knows where she is at?
3. No one knows the relationship between the father and daughter?
4. It seems to me OP, if there is a large sum of money to be transferred, the beneficiary of receiving that money would be there to collect the money in PERSON! The daughter.
Sorry to say, I would NOT be proceeding with this sale. The reason being the father is claiming the daughter gave him a signed POA, yet the father has no idea where she is. How did the father get a signed POA if he has no idea where is own daughter is?
I would GUESS the australian father got divorced, maybe transferred the land to the daughter to keep it away from his exwife, yet maybe now the daughter is on the mother' side and not his? He is <deleted> on and trying to use a forged POA to get the money back HE spent on the land and house?
If you cannot afford to lose this money, DO NOT RISK IT. This is Thailand.
People in Thailand expecting large amounts of money from the sale of land simply do not disappear.
I would NOT PROCEED UNTIL the lawyers identified where the seller (Daughter) is and verified the fact she signed this POA by speaking directly with her.