I am sorry to hear about your stroke. I hope you are feeling alright.
I have not seen anything like a spring-loaded pool cue, but that would be so perfect. It could have different spring tensions for making hits of varying forces.
However, there are a number of devices out there, but from what I have heard, none of them are particularly good. It's about trying a few until you find the one that is the "least bad" for you.
EZ-Bridge - Sanctioned by the BCA - totally eliminates the need to use your bridge hand by providing a rolling stand for your cue shaft. Sold at amazon.com.
The Cannonaid - This invention is designed for a one arm person, one handed person, somebody with a broken arm, arthritis or a bad back who cannot bend over, or someone confined to a wheel chair. This is an older one, and not sure where you can get it.
There are others out there like these. These were just the first two I found.
Shooting Aid for Disabled Bridge Hand from Stroke
Title: Shooting Aid for Disabled Bridge Hand from Stroke