I often did things like this "once". I agreed to be a second signature on his account before he could withdraw or write cheques. Didn't work the first time, didn't do it after that.
I held medications much like you did. Didn't work the first time, didn't do it after that.
I learned that enabling was doing for them what they could and should be doing for themselves. I learned to be supportive and do things like that until it was clear that it didn't make a whit of difference.
What helped me was to return to my first step...We admitted we were powerless over the addict/his addiction/his ability to manage a bank account/his ability to be responsible with medications/fill in the blank with anything that didn't have my name all over it.
Doing that saved me from the need to go to the second part of that Step...and that our lives had become unmanageable.
12 little steps saved my bacon and gave me my life back and I will be forever grateful.
Hugs