I understand your problem here. You can't afford a jolt, I think that the biggest problem might be taking a jolt to the shoulder. But if you get something new, who will test fire it?
If you can afford to, I might suggest getting a full sized .380, not an ultra compact one. the 90 grain bullets are far less energetic than a 9mm, but if you had a heavy 9mm pistol already, maybe you could get the same results with a 115 grain 9mm round that was a special reduced load, or subsonic.
I understand your predicament. I am truly glad that you are doing well, bypass surgery isn't a good thing. I had brain surgery for an abscess a couple years ago, and I'll be the first to say that it was probably much less dangerous and less painful than bypass surgery. But, like you, there was a risk of damage in case of an impact. A clot, a bleed, both the things that you need to worry about.
But, IMO, your greatest worry shouldn't be a new gun. It's any impact. drive very little. Stay away from places and activities that may lead to a whack on your body. stay off of stairs. be careful on your treadmill or other equipment.
In a survival situation, if such a situation arises, the probability that you will be badly injured during an attack has just skyrocketed. Make your plans accordingly.