When Mom had to start using portable oxygen, the doctors said both of my parents must stop smoking. They also warned Dad to stop drinking alcohol because he's showing signs of mental decline. My parents have done pretty well with this so far, but every once in a while at a family gathering, they want to indulge a little. When my sister and I don't give in, Dad grumbles, "Who's the parent here?" My sister and I disagree -- I'm inclined to let them decide this for themselves, but my sister is not. Who's right?
I'm not a psychiatrist or doctor, but if my mother was on an oxygen machine, I wouldn't let her smoke. I understand not wanting to be on your parents' case regarding every little thing, and I'm certainly not against the occasional cigarette for someone who doesn't have weak lungs, but your mother does. And this may really be about more than an occasional nip or smoke for your parents.
Consider how much you think your parents really indulge. We all fib about our vices. We usually indulge more than we admit, even to ourselves. I wouldn't be surprised if your mom already has some cigarettes hidden away -- for "emergencies." And I wouldn't be surprised if your dad's imbibing was more than occasional.
If you've avoided confronting these possibilities, you're not alone. I've found that we underestimate how bad things are when it comes to care giving. We need the situation to stay status quo. We need to go on with our lives, with care giving as a side dish, not the main entrée. For example, I avoided my mom's driving issues and made excuses with her and for her not only when she took out the mailbox with her car, but also as she became increasingly unable to find the right word or remember why her keys were in the freezer. I had kids, a husband, dogs and cats, and a career. I needed Mom to be OK -- just a little forgetful. But she wasn't OK. She needed care.
You probably already know that smoking near an oxygen tank is just plain dangerous. Anything combustible -- even high heat or a spark -- can create a fire, so your mom should never smoke when it's hooked up. If she's getting forgetful and might not remember this, indulging on her own could become very dangerous for her and your father. And as much as you might like to unhook her from the oxygen once in a while to let her have a cigarette, isn't that sending her a dangerous message? Will she interpret it to mean you think it's OK for her to do it when you're not there?