My father aged 50 yrs is diganosed with recurrent spindle cell neoplasm and is in his 4th stage. What are the chances of his survival?

It is called 'recurrent' because actually develops from the body trying to heal itself from an injury, or such. It is a form of cancer and you should be discussing your father's condition with his doctor. This cancer being in the fourth stage is not a good indication.

Tick

Only his doctor knows that, You may see if you can go with your dad to the doctor.

But life has no guarantee, none of us know if we will even wake up each morning and if we do, if we will live though the day. We should live each day as if it is our or anothers last,