Q: What is the penalty for someone who didn’t take care of their elder spouse such as withholding nourishment, and not properly helping like withholding hygiene for the person? This was the main cause that lead to the person’s death.

A:  More information would be needed. If this is an extreme case of failure to nourish, which is medically/forensically related to the death, the charge could be homicide. I would review all the details with a lawyer or contact the police.