''To the poster that asked if this thread has changed my perception of the situation, the answer is that one thing I have realised is that of my 4 close friends who are aware of the situation, not one has warned me, or suggested I was doing the wrong thing. I take this as the people who actually know me well don’t believe I’m “desperate “ or “co-dependant” or most definitely not at risk of using drugs myself, because believe me they are the type of people who would voice any concerns!''
I'm coming from a place of wanting you to put your own needs first, but what you've written above doesn't add up.
This thread has you're telling us cemented your own perception of the situation. Even though you haven't been brave enough to answer many of the questions put to you presumably because our perceptions to your answers would be negative and 'wrong'.
This tells me that you have a bit of a forcefield of denial around you 
Your friends are not the types to silence their concerns you tell us, but yet they have not voiced their concerns to you.
I infer from that that they've tried and you didn't hear so they know they are pushing water uphill.
I am not trying to give you a hard time.
I hope something penetrates the denial before you get in to a situation you can't get out of. Your own addiction. Hep c. Depression. Debt.
You also tell us that there's nothing wrong with letting him know he's loved and supported and that's a good point but you don't make it obvious to us what you get out of it.
I'd apologise for this post but I think it will slide off and you'll think I'm just interpreting things wrong.
I hope you get yourself out of this situation.