My heart goes out to you as I know how hard it is watching a dog go through something like this and how helpless you feel. I get so many emails, facebook messages and similar from people like you that are desperate. I have to say it gets to me sometimes as I wish I could do more.
There is one thing you can do for the future if your dog is a purebred Sharpei. The AHT desperately needs cheek swab samples from that breed who have mast cell tumour. If you can help please do so.. My website has donated kits to the AHT so that dog owners do not have to pay to send these samples. Without samples it is going to take so much longer to get better treatments and cures.
http://www.caninecancer.org.au/researchuk.htmlVickie can get these kits out straight away and they take about ten days to get to Aus.