Many families, when they have a relative with an addiction, believe that this addicted relative can heal on their own, without any medical help. The problem with this begins with the following: the addicted person may have the willpower to quit, but their environment doesn't make it easy for them to do so. If they're addicted to alcohol and live in a household where people consume alcohol, then they'll have to deal with alcohol around them constantly. This won't help them kick the habit.
If they're addicted to drugs and live in a neighborhood with a lot of drug use, then even if they try hard to kick the drug habit, they won't be able to. If they're addicted to gambling, but they're on their phone and computer every day, then they won't stop gambling. That's why it's necessary to seek medical help and isolate themselves from everything for a while until the person develops other habits. This way, they'll be cured.
However, it is not always necessary to quarantine yourself. If you really want to get out of it you need to strengthen your morale, you should understand well and reshape destructive thoughts and behaviors. I've seen many to follow some rules strictly which are backed by scientific evidence and enable them to learn about & redefine delusional thoughts and behaviours. example- you could join with healthy community to identify your common triggers like boredom, stress and take over control. sometimes you could use self exclusion tools, I've seen many use site blocker so they could stay away from gambling even when impulse hits. So yes, changing your environment is key, but pairing that with therapy and community gives the best shot at lasting recovery.