Sounds like a possible case of the flu. If the symptoms last over a week or if the patient has asthma, they need to see a doctor. If they have astham, the sooner the better. An asthmatic should also be using their rescue inhaler exactly as prescribed (number of doses at the shortest time interval) to prevent/minimize a flare. Also, if the are elderly or have otherwise compromised health they need to see a doctor. You need to agressively work to prevent dehydration.
Depending on other medications she may be on, guaifenesen (generic Mucinex) would be a good idea.
I hope that helps you some.
I pray that your mother is feeling better soon.
Sounds like Pneumonia to me..