With bulimia you would see malnutrition, teeth can fall out, hair loss, eating large amounts at a time, and vomiting after almost every meal among other things.
With Binge eating disorder you would see someone eating without the ability to control themselves, someone eating large amounts of food at a time, weight gain, they may experience shame/guilt afterward, and can cause self image problems.
With suicidal thinking one would likely see signs of depression, the person would have self image problems, you may see injuries on the person that appear self inflicted, you may hear the person talking about hating their life/wanting to end it all, and you may see them saying goodbye to friends and family in a way that appears it may be for the last time (would seem irregular or strange).
Communicate:
1. Tell them you are there for them whenever they want to talk
2. Make sure they know you love them, and that they matter.
Offer help
1. Offer to talk to them about whatever is troubling them.
2. Tell them you are available to assist them if they need any help, and make sure they know you will stand by them. Offer to excersize with them if they are ashamed of their weight and want help with it, for example.
Follow through
1. Let them talk to you and don't judge them for what they say. do whatever you can to help them however they need it.
2. If it gets bad then tell someone like a counselor who can help them. The most important thing is keeping them alive and you must follow through with this no matter what.
