What state does she live in where her father, without a court's approval, can commit her to mental confinement ?

Does your state/community have any resources for the mentally ill ? She needs a guardian ad litem. She also needs a psychiatric and medical health case worker who can try to find proper help and diagnostics.

Is she still married to your son ? Does he have any influence over her care?

Do you have a neuro rehab hospital in the area ?