If it all goes wrong

You may have stayed calm and respectful, and put across all your points, and your loved one still reacted in an angry, defensive way. Don’t panic. It may take them a little time to feel comfortable talking about what is going on for them, or admitting there is a problem. The work you did will not have gone unnoticed, and hopefully it will have planted a seed.

Having approached them with your concerns in a loving, compassionate way, without judgment or blame, you have made it much more likely that your loved one will come back and talk to you when they are ready.
You could broach the subject again with them after a while, and see how they respond.