Hi Looley and welcome to the forum.
I am also the mother of a 28yr son with alcohol and cocaine addictions. I totally sympathise with you, it’s a very difficult and stressful situation. Everyone on this forum has a loved one who is struggling with addictions, so we understand how you feel.
I don’t have all the answers unfortunately but if you read the other threads, there’s good advice and support from other mums, people in recovery and the forum offers advice and support on the home page.
My son lives independently, but he’s currently clean, and attending AA and CA meetings online. They introduce newcomers to the 12 steps and organise a sponsor.
Your son is still young yet, i wouldn’t give him any cash, but make sure he’s eating well., and staying away from negative influences. The Icarus trust may give you help too.
I hope and pray that you both get the support you need.
Always here to chat,
Take care
Lx