Question regarding Nephrotic syndrome

My brother 17 y/o male hx of primary MN(nephrotic syndrome) gets ritux infusion every 6 months, currently on lisnopril, has been having for the past 4-6 days bad cough and very bad wheezing. Started him on augmentin and z pack and doing abluterol nebulizer every 2 hours and it gets better but then wheezing gets worse at night, but no fever/chills/n/v/d, just the cough and wheezing, o2 sats are ok, they were intially low 90’s but now 98. Did resp panel and came back + for rhinovirus which he has got before. This is what cxr shows, radiology attending said it doesnt show anything concerning. But im worried why is his cough getting worse and why is the wheezing coming/going, is it because of the suppressed immune system? He saw peds pulm in clinic and she thinks its Asthma and started him on stronger Asthma medications and still on 50 mg prednisone and Albuterol. She mentioned that if the Asthma doesnt get better then we should get a CT scan to rule out fibrosis but my question is what do u guys think? Does ritux cause pulm fibrosis in young kids or is this just a asthma flare up with the rhinovirus. Thank you all for help