Scoopenator, You did well ! Really well.
To start with No, is a complete sentence. Just keep playing the broken record over and over. When he gets angry it is because he is not getting what he wants. You need to stay calm. If the AS threatens you or anyone in your home cal 911. If the AS threatens to kill himself, call 911.
If they say they need money for food cook them a meal or take them out to eat. that way you know it was food and they got to consume it. Any other reason for money , they need to get a job and get there own.
Another rule of thumb I use is "wait 24 hours." Yes wait 24 hours before you answer or return their phone calls. It is amazing what issues they can get through themselves when your not jumping to their wants and needs. It also gives them time to calm down before confronting you, And you are confronting them on your terms not theirs. ....Stop letting him control your life. Make time for him when you are safe, comfortable, and not busy with something. He will start controlling his own.
I know it is hard detaching with love. You'll tend to question yourself sometimes. But if it is not good for you or your peace, if it will only make things easier (for them or you) then don't do it.
Remember "NO" is a complete sentence. You do NOT have to explain yourself to him he is you son, not your spouse or parent. He asked a question and got an answer, no mater how he phrases it the answer will be no all week long.
Stay strong, don't let him play the mom against dad game with you two. Your going to have to be on the same page and same answers to the addict.
Be well,