Guardianship of Stepchild when One Parent is Deceased

[Nana2B]

My question involves guardianship in the State of: TX

Bio mom is deceased. Father and I have child living with us full time.
Sometimes father cannot be around all the time for when there are doc's appointments, hospital appointments, etc.

How do I obtain legal guardianship of my husbands child so that I do not have to have a written note or him with me at all times?

Is there a way I can do this without the aid of a lawyer since we are living on very limited income?

Thank you. Any further questions needed will be gladly supplied.

[Mr. Knowitall]

If you want to assume the role of parent, have you considered step-parent adoption?