What can my mother do if she can't breathe or has trouble breathing when lying down?

My mother has oxygen 24/7 with copd. She uses nebulizer and inhaler, and takes medications for pain, heart. She has fractures in her spine causing pain daily. She had pneumonia 2xs in hospital past few mths. She is having stomach pains alot, nausea, and doctor said she's malnourished. She dropped alot of weight. A nurse visits weekly. She thinks she might have a virus,so shes taking coke syrup for nausea., but she feels like throwing up every five minutes. She needs sleep too. But has problems breathing lying down! Benadryl didn't work or chamomile tea. What can she take for sleep? And what can help her breathing in bed????? Thank you for advice. she will probably get blood work this week, to make sure it's not cancer or other stomach problem.