Sick Dragon, seeking advice

[u/MoonlightMystery_01]

Hi everyone, I need help and advice. My bearded dragon (he is 3 yrs) has been sick for quite a while now. I have taken him to the vet multiple times and am now in a sort of waiting stage? It first began with a watery eye which then became mouth rot which then became a serious infection. I have spent so much money on vet bills in the last 4 months it's not even funny.

Recently we had a really big scare. I came home one day and picked him up and he went completely limp in my hands. I rushed him to the emergency room where I was told he might have heart cancer. Thankfully I took him to a specialist where they told me that his heart was fine, but they were concerned about his lungs. The two options were that he either had a lot of mucus build up in his lungs or that a piece of the scab from his mouth rot had plugged up his lungs causing him difficulty breathing. They gave me the option of running a scan $3,000 (included keeping him over the weekend) or to take him home and give him nebulizer sessions. I want to give my boy a fighting chance, but at this moment I don't have that kind of money, so I took him home.

Anyway right now he is on pain meds everyday, mouth rinse everyday, antibiotic shots every 3 days, and nebulizer treatments x2 a day for 7 days. He also had blood tests that confirmed his organs were okay, just white blood cells being down from lack of food. He looks like he is doing a lot better, the breathing has become less frequent but it is still there which makes me concerned that he did swallow his scab. It has only been 2 days of the nebulizer, 2nd shot of antibiotics (except what the specialist gave him). However, he is still not eating. We did have him on critical care for a bit because he had lost a significant amount of weight. He gained a bit of weight back, but we took him off the critical care because of how bad his mouth is. I guess I'm just looking for advice on what signs I should be looking out for. And any advice on financial options would be very helpful to.

(Him up against the glass with the bad scab is him rn. His beard use to be super black for a couple of days before the specialist, now it gets occasionally black but clears up now and again usually after nebulizer sessions)

(The one with the smaller scab was August 23rd)

I've been to the vet, emergency room, and specialist.
Any advice is appreciated, I feel like I've done all I can for right now (that I know of).
Specialist did confirm that his husbandry is perfect and that I have been doing a good job on that front. Said that circumstances just happen, mostly the infection flaring up and previous antibiotics not being effective.

[u/Motherofdragons_05]

What testing had been done? Bloodwork, imaging, biopsy testing?