Betapace is a non-selective beta blocker drug and so would have a tendency to cause bronchoconstriction in persons with asthma or COPD. That would become evident by wheezing. The betapace would be very likely to cause wheezing when your mom's pulmonary drugs were withdrawn. Wheezing is not characteristic of pulmonary fibrosis. You might want to ask the pulmonary specialist why, if she doesn't have COPD, she began to wheeze when her lung meds were withdrawn.
This suggests that she does have obstructive lung disease (asthma, COPD or a combination of the two). Asthma is quite uncommon at her age but some degree of what is called bronchial hyperreactivity (tendency to constrict) with COPD, is not. The betapace could blunt the beta-agonist stimulatory effect of Advair, on heart and lungs. To look at this another way, however, the beta-agonist effect of Advair might blunt the beneficial effect of the betapace. The cardiologist would be the best person to make a decision about this.
Most importantly, is the fact that, according to the information provided, she was doing very well on her cardiac drugs and the Advair and that might be the best evidence favoring the use of both.