Urgent, i have a very sick 20 yrs old cat, he is terminal, i need to know if euthanization hurts, i mean...?

I know what you are going thru, I am an animal lover. If he is in pain or unable to be active, i would euthanizide him. It is not painful, they put him to sleep and he slowly slips away while sleeping. you can hold him as he is put down. i did for mydog. i felt good because i was able to say goodbye.