Ok I've had asthma for 26 yrs and I can assure you that I do not have holes in my lungs. My son and grandsons also do have have holes in their lungs.
Your kid's father needs to speak with a doctor instead of his crazy aunt. Does he have a basic understanding of asthma? How you can't get air into the lungs because you can't exhale to get the air already there (with the oxygen removed) out? No air movement = no oxygen = death. It's as plain and simple as that.
Explain that yes your son needs the nebulizer more right now because he is recovering from pnuemonia which is a disease that puts fluid in the lungs. Infected fluid takes up room that is needed for oxygen exchange. Add in the asthma which effects the function of the lungs and it would be a disaster if he didn't use the nebulizer.
Hugs to you and hope your son feels better soon. What a frightening thing to have to go through. It's a shame that you are getting stupidity instead of support.