I see two elements to enabling...
One, as said before, is doing for them what they could and should be doing for themselves.
The other is giving that which encumbers ourselves. If I buy my son groceries so he can eat, that's just a nice thing to do. But if I have to spend money I don't have to do it, then it might be enabling.
Sometimes I think of what I might do for a good friend, just out of kindness, and that helps me decide. Also, doing something once is different than taking financial responsibility for something.
I had to get used to the fact that anyone in active addiction will not live in wonderful accommodations nor will they eat a balanced diet and take care of themselves in a healthy way. Even on the street, my son had a men's hostel run by the Salvation Army that was clean, provided hot meals and shelter and counseling if he wanted it as well as assistance getting into a program....and the Salvation Army programs cost nothing and are very good. That worked better for him than letting him live in my home and giving him meals, a warm safe bed, and the love and support of family.
Hugs