Father in Prison, can a step-parent seek custody while father is incarcerated?

[frrngtn5]

I am hoping that I am not in an unique situation. My husband and I recently discovered that his daughter has been in a situation that involves meth. Her mother's new husband (common law) it a meth addict. This is the third time is 6 years that he has fallen off the wagon. They are not currently living together but odds are they will get back together being they share real estate. The step-father was recently arrested for simple assult and possion of meth.

My husband is wanting me to seek custody of his daughter being that obviously he can not being he is in prison. Both the child and I live in Iowa and my husband is in Minnesota. It is my understanding that as a step-parent I do not have rights and will not have much pull in the legal system. Also a judge will not grant custody to a father while he is in prison. The child could be removed from the home, but would be placed either in the system or a blood relative until her father would come home and prove that his home is safe.

Any ideas or suggestions for me on this?