Stealing is a Crime !
You seem to have lost sight of this absolutely fundamental fact.
Call the police. Drop into a station and ask them what to do. It is their job to handle such things.
Also note : if he steals money, does he also steal drugs ? Does he take in prescriptions which he knows are false ? This could be the tip of the iceberg - criminals actions like theft rarely stop at one thing. This one person could do tremendous damage to you, your business and your reputation and indeed your family.
Any policeman will tell you that when you uncover one small lie, it's often the start of a trail of lies, sometimes leading to the discovery of bigger (and unrelated) crimes. It's your duty to tell the police.
He is still a very trustworthy person for me because he helped me in my difficult times.
Understand that criminals often do project a nice and trusting personality - it's part of the requirement of getting into a trusted position. As your own indecision shows, it also helps keep them from being punished.
Don't fall for that old con.
Should I talk to him about this or report him straight away ?
Police first. Get advice from people who understand crime.
It's what they're there for.
Or let him fulfill his needs by stealing that little amount of money.
No it's not OK.
If this person simply needed more wages, then they should simply have asked for a raise. You don't sound like an unreasonable person, so they presumably have no reason to think you would be unreasonable.
What they are doing is wrong. There are many good people who would do your job and never steal from you under any circumstances. Why should this person get the benefit of your kindness when they have no moral right to it ?
Stealing is a bad habit
Stealing is a crime. That all.
Would you steal ? What would it take to make you steal ?
It is an exploitation of your good nature.
, and I want to share this with him, and make him aware that I know about this incident, but I don't know why I feel guilty about the idea of bringing this up to him.
Do not confuse your morality with this persons. My experience is that criminals feel a sense of entitlement and have no real sense of right and wrong. No amount of telling them about right and wrong will give them one.
My view is that this person has cynically manipulated you and your trust. You feel guilty because they want you to feel that way.
I, unfortunately, have dealt with too many crooks who do these things. It's what they do. It's a plan, part of how they get into positions of trust and exploit them for as long as possible with the minimum of consequences.
Do not let this person get away with it.
Mercy is for the court (if it ever reaches court). They can decide, with a more complete knowledge of the individual's circumstances and true history, what sentence if appropriate - a fine, repay victim, perhaps prison. That's what courts are for.
You may not really know the person you think you do. Five years may sound like long enough to know someone, but I've seen ongoing thefts from employers that went back twenty years when people started digging into the facts.