NO it will NOT effect the tune or hurt the BCM/PCM or any other module. In FACT,,, the OWNERS MANUAL recommends "Disconnecting the Battery"
for long periods of stowage.
When you disconnect the battery you will resert the learned LTFT data, all the FOB Memory data and fuel efficiency data will all reset & default to the factory settings. You will also have to re-sync your FOBS. You also cause the PCM to set all of the EMISSIONS NOT READY flage and if you have to get an emissions check, you will have to go thru a number of drive cycles before the FLAGS set to ready.
The LTFT Data will regenerate and learn after a short drive. You just have to reprogram all the seat/dash memory settings manually.
Why not just FIX the problems that are causing your battery to drain??? Its not all that difficult. Insert an AMP meter in series with the NEG Battery Cable and read the DC Amperage that the BCM and PCM draw after the system goes into sleep mode. It should be very close to 0.020 AMPS or 20 milliamps. At that minimum current draw, the car should be able to sit idle for inexcess of 30 days (seen it start without any issues after 2 months of storrage if the battery is in good condition and fully charged!)