Service tax leviable???

You can claim basic exemption limit of Rs.10,00,000 if you are liable to pay as a Service Provider. However, If you are liable to pay as a Service Receipent ( under Reverse Charge Mechanism) then there will be no basic exemption limit on such reverse charge.

File Nil ST-3 return for the period Oct-Mar 2016 by showing the actual turnover and claim the threshold limit.

The intention of seeking registration is not stated. Also one has to specify at the time of registration as to when from services are provided or intended to be provided. Individuals are not required to seek registration under RCM If your friend is a service provider then exemption can be availed to the extent of 10 lakhs. If he has intends to avail input credit then abatement cannot be claimed and threshold exemption would also not be available. He can surrender the registration if erroneously obtained or file nil returns. Suggest you provide more inputs so that my learned friends can opine appropriately.