Cheque Biounced

1. Person X gave some Principal amount to some 3rd Person Y. 2. After some time Person Y told Z to pay interest to Y on his behalf (Because Z had business relations with Y). 3. Person Z gave a blank cheque of back date of 2011 to Person X. 4. Person Z is already give enough interest of more than Principal amount to Person X. 5. Now Person Y is dead. 6. Person X is still claiming Person Z to pay Principal amount. 7. Please note that apart from cheque there is no written prof of what person X gave to Y, and no proof of what Person Z gave to Y. 8. Person X has filed a case in court on basis of that back date blank cheque. In which he himself filled amount and date with this own handwriting. 9. Person X never gave that blank cheque to withdraw when date was not expired for that cheque. 10. I got summon also for same. Now really worried how to proceed further. Local lawyer say first you need to get bail . Can you please let me know what can we do proceed further and can son gives bail to his father as a witness.