I am the mom of a 27 year old son who also started compulsively gambling at 18 years old. A lot of your story could be ours. He has stolen from us, our business, his siblings. He has also slashed his wrists a few times. He was living with a roommate and left a suicide note and his poor roomate was also frantic. It is hard to believe that gambling can drive them to these dark places but it does.
You did what you did bailing him out because you love him and didn’t know better. You are probably starting to see that as long as you keep giving he will keep taking. This isn’t an issue of love… he has a very strong addiction that renders him powerless over gambling.
Unfortunately they have to really feel the consequences of their actions. As a mom this is brutal and requires every ounce of strength you have to watch them fall and suffer. From my 9 years dealing with this ( I am a slow learner:)) there is nothing you are going to do or say that is going to make your son see this as a problem. Only he can decide when he has had enough. You can help the process along by taking a huge step back and getting yourself to a GamAnon group. I have been going for 3 years and the support, gentle suggestions and friendship have honestly made this nightmare bearable.
Keep writing and talking. All addictions love secrecy and once you bring them to the light of day they don’t have half the power!
Take Care
Cathyx