Ofcourse it is possible for an IAS officer to treat patients but for that you will need to have a MBBS degree and a license to be a doctor then only you will be eligible for treating patients as a matter of fact anyone with these two things can treat sick patients but without these never.
Hope it helps you
Yes, if you have a valid medical degree and a good experience, then you can treat a patient even if you are an IAS officer. In fact, there are many people who have helped the patients by treating them even if they belonged to IAS. Adding to your information, Modi Government is planning on involving such people who are in IAS with a MBBS degree to fight against COVID-19 too.