I see some big red flags.
He's in prison. Kinda says "felony" to me. He will always face employment issues. And because it was driving related, will be be allowed to drive or whould you be signing on as the designated driver?
AA literature and sometimes meetings are often available in prison. Lots of religious organizations visit prisons. Has he taken advantage of what's been offered?
I suggest that if you see any relationship with this man you BOTH speak clearly. Anything less than that would simply be unfair. Honesty should prevail.
AND...
ACTIONS. Let his actions speak! Talk, as they say, is CHEAP.
And, I forgot...
WELCOME! Make yourself at home!