Hi, fellow Texan! Kim, I am glad you came here for support and answers. Plenty here. My wife also has NSCLC, and is Stage IV. She has survived 21 months already. If your mom is getting radiation, especially on or near her trachea, she may experience some loss of voice and difficulty swallowing, but it does get better after the radiation is over. Also, having chemo and radiation at the same time, she will tend to get very tired and more importantly dehydrated. She will need plenty of liquids, whether she wants to or not. It can land her in the hospital if she doesn't. I would ask the dr. if it would be wise to have a weekly IV of saline solution to help prevent this.
Your mom will need to keep nourished also. And she will not always feel like it. That's why it is so important for someone to keep track of her and be sure she is eating, even if you have to go totally to liquids. Sometimes you have to insist. It is for their own good. My daughter called me the "food Nazi" because I was always poking food at my wife. We found that a little food every two hours worked better than the normal three meals a day. It also helps fight the nausea, with food on the stomach.
Your mom has to realize and come to grips with the fact that it is no longer "business as usual". She can't return to her isolation like she has. It is not good for her to be alone through this. She will need to reach out to people to help her, even if she doesn't want them to visit. You are right, "she needs more than you". It is hard, but it must be done in order for her to fight this beast.
As for addiction to pain medication, our oncologist told us that as long as the does covers the pain, it is not addictive. It is when your dose is significantly above the pain level that addiction can occur. My wife is still on low dose morphine since her spine is damaged from the cancer, and we check it out to be sure the pain is covered and not a lot more.
You will need support also. I had to learn to reach out and seek help myself in taking care of my wife. I needed breaks and someone to talk with. Good luck and blessings. Don