I get that he's family, but family can be wrong. Arguing with someone who has made up his mind, is without a medical degree, who is also not your surgeon, can drive one nuts. Tell him you would like his support; not his advice. He's already given his opinion, and it's time to stand up and let him know you heard what he had to say, and you're not taking any more advice from him. Thank him for caring, and tell him what you need now is support as you make your own decisions. If that works, great, if not, you might need to stop discussing the topic with him, and just let him know the day of when you're at the hospital, etc. With the current restrictions in many places, you are unlikely to be allowed anyone in the hospital waiting room, so you can use that as an excuse as to why you didn't tell him your surgery date.
I also suggest you get ready for him to try to butt in and tell you you need heavy PT, or more of it, etc, after your surgery. Make up your mind now how you want to recover, and don't let ANYONE push you to do it their way. After surgery you're going to be weak, tired and vulnerable, so making your decisions now will enable you to keep to your plan and ignore anyone who tries to push you into their way of recovery. Your brother's injury recovery is a totally different case and what worked for him will be very unlikely to work for a surgical recovery. His knee was injured; yours will be something altogether different, therefore needing a different recovery protocol. But that doesn't stop strong and/or pushy people from trying to guilt others into doing what they think you need, even when it's contraindicated. Having a plan in place will enable you to keep to your decisions when you're at a weak point in your recovery.