Hey, sorry to hear on your the bad news that hit on your family. My late mum had the same case last year but she lost the battle.

Just sharing from my experience, doctor knows the best. If you think the doctor is hiding something, try seek their opinion when your dad is not around. Probably they are hiding from the patient not knowing how to break the news, or try get all the info you have with medical report etc and get second opinion from diff doctor.

Stage 4 doesn't mean on timer. My teacher and my aunt both has stage 4 colon cancer but they survived. Disclaimer: im not from medical-background, but as far as I know, stage 4 means the cancer has spread to different part of the body. As long as it doesn't affect the vital organ, I believe there is still hope.

You know your family best. Sometimes, too positive and denying all the bad news can be toxic. Try get doctor's advice, do what you can. *touchwood if doctor said there is little to no choice, then please resort to tender loving care.

Also, while waiting for medical expert, try google up some info regarding emotional support for cancer patient. They will tend to get overwhelmed with emotions, usually in denial state, then acceptance, treatment, and lastly lost of hope. At least, that's what my doctor told me.