Hey Don,
I agree with Graham and his wife. Singing involves the chest and your chest needs time to recover from the trauma of the invasive surgery. It will be good to get back at it but I think next Tuesday is far too soon. On the other hand, you're very good instrumentally so if you can get by that way it may be a good way to ease your way back. Just take it easy and don't do any heavy lifting. Remember, we're all praying for you and whatever comes your way.

God bless,
Don