I had IPF before getting my bilateral lung transplant. My first advice is ask if he should be on the machine all of the time. Try to keep walking as much as possible even if it is just going to get a glass of water. It is like a spiral effect, the less you do, the less you can do. I am not sure how low his numbers are getting. I was on level 2 for a few months only when walking or doing any type of activity. Then I needed more oxygen as time went on. However, I kept pushing until I wasn't able to anymore (needed level 30, which is only available in the hospital).
Since having my transplant, I have had regular bronchoscopes. During 2 of the bronchoscopes, there was inflammation noticed, which can be a sign of early rejection. Due to having issues with my esophagus (had hiatal hernia repair year before transplant), it can cause issues with the new lungs, so I need more bronchs than usual. However, they just had me go in for therapeutic infusions for 3 days in a row each time to combat the inflammation. It's almost like a reset.
I also had the issue of losing weight, becoming malnourished and had a protein deficiency. My doctor had me drinking ensure high protein shakes (4 a day) to combat this before and after the surgery.
Try to get all of the tests done prior to him getting too bad. Since I was already at level 5 and still wasn't getting enough oxygen by the time my regular pulmonologist referred me to the transplant team, they fast tracked me. I have spoken to others and it seems to go much smoother if referred earlier. When getting the tests at the hospital I was on level 8 and wasn't able to speak in a full sentence (not enough oxygen).
I would also advise, if your husband likes pomegranates, grapefruit, or their juices have them now when he still can. Other things that he will not be able to have are: sushi or anything made where it is prepared (due to possible cross contamination), anything less than medium well done meat, unpasteurized cheeses, goat or sheep cheese other than pasteurized feta (need to make sure it is pasteurized), buffets or smorgasbords, and unwashed vegetables or fruit. For the first 3 months, no outside meals. It has been almost 8 months and I still can't have bananas or plantains (too high in potassium), papaya, mangos (too high in sugar), or more than 1 cutie a day.
I believe that if the lungs fail, you are put back on the list. However, from my understanding, it's not that you drop if it happens. If you have any other questions, please ask.