How can I express my sympathy to my client's grandfather who has cancer and is undergoing surgery?

Hello, do you know the illness? If the patient doesn't know the condition, I suggest asking, Grandpa, how is the recovery from the operation? I'm a little worried. Remember to eat. When I come back to see you, it's almost the same. If grandpa knows the condition, he can say: Come on, grandpa, the operation can be cured. We will always be with you. You'd better go and see for yourself. When you are old, what you need most is the company of your family.