Have realistic expectations

Just because you have outlined your worries, don’t expect your loved one to begin eating normally. You wouldn’t expect someone with cancer to miraculously get better without support and treatment, the same goes for eating disorders. Recovery can be a long and difficult road, and they will need your support every step of the way.
Try to see things from their perspective, ask about how they feel, what they feel afraid of etc.

Think of something you are scared of, now imagine having to do that that several times a day. That’s what you are asking someone with an eating disorder to do. Alcoholics and drug users never need to see or use alcohol or drugs again in order to live, but people with eating disorders have to face their demons every single day in order to stay alive. For this reason eating disorders can be seen as one of the most difficult illnesses to overcome.