Is it permissible to use a diabetes medication prescribed for the the mother and dispensed by health insurance, given that the daughter is employed and pays into the insurance?

If the health insurance is cooperative and permissible, then it is not allowed to violate its terms or to deceive it. If the mother is deceiving the system to obtain medicine for the questioner, then that is not permissible, and it is not permissible for the questioner to use it. However, if she takes the medicine for herself and then the questioner takes from it when needed, there is no harm in that. If the insurance is impermissible, then the mother is allowed to take from it an amount equal to what she paid or what was paid by the one who referred her to it, and she is allowed to obtain it through stratagem.