Concerns about a upcoming surgery

Patient: Hello!! I have this person very close to me who is going in for surgery on there shoulder tomorrow. This person was told that during the procedure they will have to stop their heart and put them on a breathing machine for the time of surgery (5-6 hours). I understand that that is the thing needed to be done for certain operations. Now on top of that this said person also has brain aneurysms and clogged heart arteries. What are the chances of this person being able to begin breathing on their own after the procedure is complete.Thank you for your time.

Symptoms: None