It is almost impossible for the husband to make those decisions or carry out those actions while incarcerated.
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He cannot control her health care proxy - that is her decision alone and he (nor anyone else) has any say or control in that. You don't say whether or not her husband is incarcerated by the State or in a local jail - which might, but not necessarily so - make a difference to a judge. If she's not being treated by a doctor for her depression, that's the first place to start. If she's already under a doctor's care, you may want to let the doctor know about her current "bad episodes" so that hopefully it can be dealt with clinically. Good luck!