There's no problem in asking for help. The problems, as I see them, are:
1. Assuming the worst possible intentions when someone doesn't help you. Maybe something else happened and she was truly unable. Things change.
2. Only having one place to go to if there's a problem. If one person can't help, try someone else.
I think, without those two things in place, there is the potential for an unhealthy, dysfunctional relationship.
2) Sometimes people are in situations where their family is the only one they can turn to. It happens. Generally it doesn't happen for someone's entire life, but in times of great need, support systems tend to break down. That's when famliy becomes even more important.