opt out of disability tax credit

I would like to choose to claim 100% of medical expenses for my client rather than using the disability tax credit (which client is approved for and has been claiming for a few years) as with nursing home and other medical costs it is more beneficial to claim those costs rather than using the DTC plus a $10K limit on care expenses. How do I select to NOT claim the DTC within the Turbotax program without overriding on the DTC form or T1 line 31600? Assume if I override to set the DTC claim to 0, I will not be able to efile this return.