Incorrect hotel bills reimbursement issue

My friend has asked to resigned from his service due to putting few cancelled hotel vouchers for reimbursement. The amount has already credited as per the TA submitted. This is not the fact that my friend has not stayed in any hotel or did not do his outdoor job. But the bills placed were not from the hotels where he stayed but well under the limit as per the travel policy (swap the stay). Now the management has terminated his service by a force resignation on this ground and has send a lawyer notice regarding recovery the incorrect hotel vouchers from his F&F. While studying the F&F thoroughly we found that the employeer has not considered the 1 month notice period payment as per the appointment letter and also deducted the days frm the settlement of which the hotel bills produced. Now my question is - 1. Can the employeer decide not to pay the notice period incase of force resignation. 2. Can the employeer recover the entire amount from full and final without a consent. Also ask to pay the balance if the amount is not sufficient in the f&f settlement. 3. Can the employeer stop producing the relieving letter after submitting a resignation and handing over the assets. 4. If not paid the balance amount, can the employeer take this matter to the civil court. How strong would be the case for our favour and what should be the main point of argument. Since he is jobless, paying balance amount would be quite difficult. 5. How can we reduce the liability. Is it possible to submit the actual hotel bills stayed and ask to deduct the delta. All original bills are available and can be produced on demand. 6. Do you suggest to send the employeer a reply against the letter recieved stating our points like notice period payment, additional days deduction and also considering the actual hotel bills and deduct only the delta amount. What kind of reaction we may get?