From What I read, your band is a moneymaking (I hope) enterprise. It is a business. The work ethics and productivity of an "employee" have slipped to an unsatisfactory rating and this person is now an anchor and is retarding the forward progression of your group.

In all fairness, You should sit down with Her and her mother, lay out the problems that you and the band are having and advise her that at this point in her career she is a detriment and not an asset to the group. Tell her what you expect of her as a viable group member and this should include the attitude bit. Then offer her and her mother a trial period to correct the shortcomings. If this doesn't work then let her go. Who knows she just might return to her former self. Either way, you have made it known that the present situation cannot and will not continue.

AS a working individual, I put bread on my families table first, then I am willing to share with the less fortunate. When the less fortunate start to take away the bread from my family, and it comes to a point that my family suffers badly, then it appears that the less fortunate must find someone else to provide for themselves. There is an old saying that "Charity begins at home"

Sailor DAn