So nervous about my mom's surgery

Hi.. My mom is scheduled to have both a mitrial valve replacement and a single coronary artery bypass at the same time on Feb 27th. Shes 67, but has a lot of issues with her lungs. COPD/emphysema.. and only has about 50% of her lung use. She had aspiration pneumonia about 30 years ago. She had to have her stomach pumped, and they had her on her back afterward, and they left her unsupervised and she vomited.

She was in a coma for 6 months, died twice, 2 collapsed lungs. She woke up, she was 89 lbs, she fought her way back, got her strength back, her memory, was able to work her way back to getting an apartment so my brother and I could go back with her. Shes definitely a survivor, but I am so so scared about this surgery. Her surgeon said that she wasnt too worried about her heart during the procedure, as much as she was worried about my mom getting pneumonia after the surgery. If my mom end up with that, we are worried she wouldn't survive it, seeing everything her lungs have been through. She was in the hospital last year after having the flu, and having issues with her lungs and breathing. Being on a heart/lung machine for that long long during surgery scares me, and I just worry her body isnt strong enough to handle it.

Has anyone had these type of lung issues, and was okay after? Obviously everyones journey and outcome is different. I guess im just looking for anything optimistic. I wont share my concerns with my mom because shes got enough to worry about, and it wont help her anxiety going into the surgery if she thinks im worried. I hope everyone here who has had this surgery is healing well, and in good health and spirits!