●"I wish you a smooth operation and soon**. "
You're going to get through this, I'm always there for you. "
I know that surgery may be intimidating and unsettling for you, but trust the professional abilities of the doctors and they will definitely do their best to help you. "
Whatever help you need, I'm here to help. "
I am sure that you will soon be healthy and back to your normal life and work. "
It's important to show your care and support no matter what you say so they don't feel alone. 
1.Sincerely:Be sincere in your words and don't say things that you feel you can't do.
2.Avoid being too emotional:While expressing concern, it is also important to control your emotions and not be overly agitated or sad so as not to make your friend feel uncomfortable.
3.Respect for privacy:While expressing concern and support, it is also important to respect the privacy of your friends and not to ask questions that are too personal or sensitive.
4.Encourage a positive mindset:In words, you can encourage friends to maintain a positive mindset, but don't impose your own ideas or values.
5.Practical help:While expressing concern, you can also ask your friend if they need some practical help from you, such as helping to take care of the family, handle affairs, etc.
In short, when expressing concern and support, it is necessary to consider the actual situation, pay attention to words and attitudes, respect the feelings and privacy of friends, and avoid unnecessary pressure and burden on them.