Hi there, I'm sorry to hear about your mum. I'm sure there will be no more than normal, that's providing there are no chemicals in there that may react with any treatment she will receive. I lost my dad to lung cancer nearly 6 months ago and he too smoked for 50 years and the cancer was caused by smoking. I absolutely hate smoking and what it does and what it's done, but like you say the damage is now done. If it helps by making them less stressed then that has to be a better scenario to a already difficult time.
