I am sorry to hear about Rolex's situation.

If those multiple masses have been checked and are just fatty lumps (lipomas), then these would not contribute to an issue with his breathing. Rather they would need to be nasty tumors that have spread to the lung (thus decreasing the normal lung tissue required for getting oxygen into him) to have an effect like this.

Therefore, we have to consider that his breathing issues might be due to something else. That said, there are a wide range of potential issues that could give him trouble breathing. This includes heart disease (which can cause fluid to trickle into the lungs), lung infections, asthma, upper airway disease, or even a different internal tumor that has spread to the lungs.

The only way to know for sure and to appreciate if there is anything that can be done to help his breathing would be for your vet to have a listen to his lungs and a chest xray (so that you can see what is compromising his breathing). Therefore, you might consider discussing with your vet about having a chest xray before making any decisions. And if there is something treatable then you may choose to treat (and if there is something bad, then you could choose to euthanize.) That way you will know your choice is the best one for him.

I hope this information is helpful.
Please do let me know if you have any further questions.
If you have no further questions, feedback is always appreciated.

All the best,

Dr. B.

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