Hi & Welcome to HCM.
I appreciate your generosity and gesture towards your friend.
You will not be considered as an eligible donor unless you stop
smoking for at least 8 weeks prior to donating the kidney.
This is because there are many known health risks from smoking
1. It can cause potentially life-threatening respiratory complications during or immediately after
anesthesia.
2. It may also increase the risk of developing
blood clots in the leg veins which can break loose, travel to the lungs and potentially cause death.
3. It causes increased mucus production and a decreased ability to clear the lungs which can lead to
pneumonia.
4. It causes decreased
wound healing.
To be eligible you must quit smoking first and after 8 weeks you can donate the kidney to your friend after getting the pre-operative medical fitness.
Since smoking is associate with a number of diseases of the heart and the lungs and various cancers so, it's better to quit smoking ASAP.
Hope I could answer your query.