1) you should not have purchased any property in Udipi if you knew your brother nature of fabricating documents .
2) POA for sale of property requires compulsory registration . mere notarisation of POA wont suffice .
3) sub regsitrar wont accept any sale deed based on POA which is not registered .
4) you can carry out construction on said plot . take bank loan for said purpose . if property is mortgaged to bank your brother wont be interested in fabrication of documents for selling your property .
5) deploy security guards on the site