I am most sorry to hear of the troubles you are going through with your loved one. My prayers are with you and your family. I wanted to share some things with you that I know, and hope that it might help you in some way, if any.
Chronic obstructive lung disease (includes emphysema, chronic bronchitis or asthma) is the most common lung disease causing shortness of breath in older adults. Repeated lung infections can cause shortness of breath by damaging the lungs also. I am not sure what tests have been preformed, but all of the above should be taken into consideration and thus ruled out as a cause.
Exposure to any kind of air pollution, fumes,chemicals dust or smoking can eventually damage the lungs and produce these symptoms as well. Especially if the lungs are already comprimised.
I know this must be difficult without medical coverage, but it is important to try to get her in for additional medical care. Certain medical centers will work with you on payments for the medical bills if you explain your financial delimma and agree to the specific repayment terms. This may be something you could look into in your area.
I again wish you the best recovery, and a sure diagnosis to get her back on the road to recovery.
If you nee anything else, fell free to write again so one of the many specialist can assist your concerns.