Amber's just signaling her virtue, regarding her sister.
If Amber truly cared about her sister, she would've stayed in Joplin, Missouri, in that good job she had, rather than chasing her former boyfriend, down to Tucson.
If she were still back home, she could be doing a lot to help her sister.
It'd be like old times for the three sisters, April, May, and Amber, all together again.