Hello...The addict in my life is my 21 yr old daughter. I to still have trouble with the whole "addiction is a sickness and not the result of free will " thinking. While I see that when they are actively using it is a sickness, but when they have stopped for awhile an the drugs are out of there system an they start using again..that to me seems more like a choice. An if reaching their bottom can cause them to stop, that again seems like it is a choice. Or extremely low willpower.
I'm not saying it is, just that like you I'm having trouble grasping the whole concept. Maybe someome on here can explain.