Ok, I didn't want to respond to this until some other people had. For starters, why is Dad still on pain killers? What pain is it killing where? My mouth was so sore after radiation it was 4 months before I could touch 1 cigarette a week, much less really smoke.
Now returning to smoking is a really dumb idea as I found out. After 6 months of being smoke free, I started with a cig a day and kept it to that pace. 4 years later, I had a new cancer, now of the voice box which caused me to become a total laryngectomee.
Your father may be viewing this smoking issue as he already has cancer so why not smoke. It is going to kill him anyway. Well, he got clean reports so he has a shot of making it, if he wants to. But I can tell you, that quitting smoking is 'pure hell', but quitting smoking when you have other smokers in the house is 'ABSOLUTE PURE HELL'. The smell will drive you nuts. I suggest all three of you pick a goal of someplace you would like to go, a cruise, a trip to Europe, or something you would like to buy, and quit together. Put the amount of money each of your would spend on the butts in a jar daily and go do something special. Those who cheat by 1 cig, have to pay a penalty fine of the price of two packs. It won't be fun having an entire household quit all at once, but walks around the block do help. Trust me, if I can quit it CAN be done.
You're only 19, but think of all the bucks you can save over the next 50 years by quitting NOW. And it may just get your Dad and Mom to quit also. It just might also save you going though this hell somtime down the road. The propensity to get this disease is hereditary.
Good Luck and take care,
Eileen