Most Helpful Guy
You are WAY out of bounds with thinking that you have the right to manipulate the situation and cause your friend's relationship to break up. If you do that and she finds out, she will no longer be your friend. She will spend the rest of her life being miserable and comparing every guy to "the one who got away." The only way for her to realize that he is a mistake is to let the situation run its natural course. If they are not meant to be, something will happen and it will end.
Before you go appointing yourself to be in charge of someone else's life, you need to have your life in perfect shape. As long as you have an attitude like this, you need to spend your time focusing on your own problems.1
Most Helpful Girl
If she's happy, there's nothing you can do about it. It's entirely up to her if she wants to leave. They've been together a year so she obviously has feelings for him. You just have to wait it out and DON'T get involved or sabotage the relationship. She'll realise her mistakes herself in her own time so let her realise by herself otherwise you'll just look like a bad friend in the end. She won't be happy about you saving her from her "lame boyfriend", she'll feel hurt and betrayed and definitely won't view you as being right.1