Dear Sumit,
If one reads between the lines then it can be deduced that the MNC has played a game with the sick employee. Without directly removing the employee because of his prolonged absence, they have transferred him. Therefore, creating conditions that are most unsuitable to continue his employment. By issuing transfer order, they have avoided regular procedure to handle cases of indiscipline. Now if the transfer order is not obeyed, it will be considered as misconduct and it will become ground for his termination.
The other side could be that the H.O. might have taken decision to transfer him as they did not know the employee is sick and has not been attending his duties regularly. Therefore, the transfer could be just chance also. If this is the situation then the sick employee may put up application for annulment of the transfer on compassionate grounds. However, this is remote possibility.
Your query is one labour law related to the employee transfers. Nevertheless, there is no law as such. Most of the companies while issuing appointment letter include clause on transfer which generally says that they reserve complete right to transfer an employee from one place to another. Therefore, nothing can be done on that count.
Thanks,
Dinesh Divekar