16 year old cat just diagnosed with full blown diabetes Options

[eamcjrt]

Hello, just looking for some advice. Our lovely girl who is 16 has for the last couple of months not been herself. She cannot groom herself anymore, her coat is poor. She is very stiff on her back legs, very thin and just sleeps all day and night. She is also drinking copius amounts of water and peeing a lot! After some urine and blood tests she has just been diagnosed with full blown diabetes. Because she is thin and only just got it the Dr. expects that it is probably due to some sort of tumour probably in her stomach. Her sister died 3 years ago of stomach cancer. What do I do. We love her dearly. Do we put her to sleep or do we investigate further. Do we find out if it is cancer. If it is just diabetes do we put her through twice daily injections and hope that this is all she will need. I am really torn and would like to know if anyone has had a similar problem in an old cat and what did they do?