Hi Asha, you need to provide more information before we can give a proper answer. However, a bond is valid in India only in certain circumstances. It is mostly valid where you have provided some specialized training to the employee, and the bond is intended to cover those expenses. Mostly, courts have discarded bonds where the training was not formal classroom training given by external trainers, but again, it depends on circumstances.
In any case, you cannot prevent him from leaving or force him to work where he does not wish to. At best, you can ask him to pay the amount of the bond and can file a civil suit for the same.