bird fanciers lung, need ideas to rid home of bird dander

After living with our African Grey for 15 years, my husband was diagnosed with NSIP secondary to bird fancier lung. His oxygen drops below 85 when he walks so he is on oxygen. His doctor wants him to stay away from all birds now. Does anyone know what steps I need to take to make sure the house is completly free of bird dander. Do I need to wash the walls down, with water only or a soap product or will it be good enough if i used a duster, like a swiffer duster with an allergy spray or not. Our parrot no longer lives in our home. Do I need to get the ducts cleaned. If so do I wash the walls first than clean the ducts. How about the filter. Any help ideas welcome.exes

Occupational Asthma, Worker, 2/16/2015, 2/16/2015,