Hi there ~
I understand your concerns. Cocaine addiction can be a serious disorder and life threatening depending on the amount of cocaine you are currently using. The small bites on the neck and arms with dehydration
followed by vomiting
with whites maggots like things and diarrhea
after sleeping in a filthy place are all self explanatory with the usage of cocaine and having poor hygiene. You son needs to be in rehab after acute detox and you need to have him court ordered to treatment. I hope you understand the urgency of the situation, consult a psychiatrist
and the local community social services, have him assessed by them and get him to go to treatment even if it is involuntary for the time being as he is a threat to himself. I believe he has a chance for recovery even now and you need to get him to go to the doctor as soon as possible.
I hope this helps. Take care and have a lovely day!