How?

How do you tell someone that you think they have bigger problems than they are admitting?

How do you call someone out who is in an unstable mental state?

How do you get this person help when a. they don't want it? and b. the law isn't on your side?

How do all the things that keep you going on a daily basis not mean anything to this person?  As in, your faith (they have none).

How do you convince a person that you love them unconditionally in spite of everything they are going through/dealing with/that is in their past and you always will; yet it doesn't mean a lot to them?

How do you "not worry" about a person because you have to take care of yourself and your four year old; but that person's problems are always on your mind and your heart?

How?  How?  HOW?!?!?!?!?!