My dog is 12 1/2 and had a seizure. I took her to the vet and they said she has heartworms. Started her on the medication and the next day she had another seizure. I rushed her in again and they did X-rays to find out she has cancer(I’m not sure what kind) but it is on or near her lungs. They put her on seizure meds and it doesn’t seem to be helping. She rests most of the day and when I get her up to go to the bathroom or get home from work, she has a seizure. And now she seems to be a bit unsteady on her feet while walking. I took her for a short walk and she walked good. She has lost some weight, I can feel her spine very easily, but her stomach seems to be a bit bulgy. I want to know if this is all from the cancer or could she have possibly at something toxic or something that could block her to cause these symptoms? And is this most likely the end or is there other things like diet and vitamins I can give her that would help?