I'm sorry to hear about your mom's situation. It sounds like a difficult time for you both. Here's a prayer you might find comforting:
Dear God, please comfort and heal my mom who is suffering from a cough. Grant her relief and restful sleep. Help me to trust in Your plan and find peace during...
I hate sleepless night, pray ### go to bed and sleep, pray she stay out of ###'s room, pray downstairs stay quiet and not make so much noise, pray healing for ###.