distraught mum

my son started taking cannabis at 15yrs old progressed on to coke and then took anything he could. he had a good schooling, did well at exams but since leaving school has got in with the wrong people and now is at rock bottom; he hasnt lived at home for 18 months, was in a flat with a decent guy and seemed to be changing his ways but alas, has recently been caught and is in court for shoplifting - this i never ever thought would happen - he is on the verge of being kicked out of his shared flat and doesnt give two hoots what happens to him - he hasnt got a problem according to him, i have arranged counselling in the past but he just told a load of lies, and he is diabetic to add to problems. he is in and out of hospital very ill with the effects of drugs and alcohol and not doing his insulin or eating properly. as a mum it is breaking my heart to see him like this, but he wont accept help. we are a normal hardworking family, - he has never worked, and hasnt been bothered - he thinks the world owes him and is now borrowing money knowing he cant pay it back so has got people after him - if the drugs dont kill him then i fear someone will - how has other parent s dealt with issues like this please because i am at my wits end