No I am not a vet. I have worked as a Vet assistant and been involved in dog health care, breeding and hehavioral fields for over 20 years.
Many dogs develop tumors late in life and your dog is definitely at the end of his life span. Labs have a general life span of 10-13 years but often develop quite a few health issues when they get older. They often develop arthritis that makes it uncomfortable to rise. They can also develop degenerative myelopathy that affects the spin and makes movement difficult as well and can lead to a loss of sensation in the rear and incontinence, etc.
These condition can lead to stress and pain which can cause excessive panting. Dogs can also develop congestive heart failure like humans do. So to answer your question, depending on the cause for her difficulty breathing, there could indeed be a medication that might help such as enalapril or lasix that might help reduce fluid buildup that can lead to problems breathing. Read more on treatment of congestive heart failure here:
It would require that your vet do some imaging of the chest to determine if this is congestive heart failure. I would start there. I do know how hard it is to let your dog go and recently had to euthanize one of my own. It is a hard decision and usually is based on the dog's quality of life. If there are things he still enjoys and he isn't in pain all the time, it probably is not quite time. Most owners seem to know when that time comes as the dog can not do anything they enjoy and usually are in pain that even medication can not relieve. Now you might help him with rising by using a sling when he wants to get up. That might help if he has some arthritis. Getting up is the main problem when a dog has arthritis. Once they are up and moving around the discomfort is relieved a bit.
I hope this information is helpful to you. If you would like any additional information or have more questions please don’t hesitate to press the reply to expert or continue conversation button so I can address any issues you still have . If you do find this helpful, please take this opportunity to rate my answer positively so I am compensated for my time.