Our 17 yr old cat has a lot of phlegm that drips out of his mouth when he eats. Also, whenever he starts purring, he makes a loud rattling sound, has to open his mouth to breathe, and is so uncomfortable he paces around until the rattling stops. We can stop him by blowing at his mouth when he inhales or tipping him upside down. As a result he no longer wants us to pet him or hold him, which is awful for all of us. He was hit by a car at the age of 4 and his head/throat is slightly askew. He's been on thyroid med for years, and had a large growth and half his thyroid removed 2 yrs ago; the rattling started 6 months later. Can you help?