How can I get my step-dad to help out more with my mother's care?

Of course you are tired! You don't say if you live with them or if they live with you. You may have to ask adult social services for some help. They mmay be able to refer you or help them or something so you aren't solely responsible.
Please try that and let us know if you get help.
Carol

I don't know about other states, but Virginia has several options through Medicaid called Home and Community Based Services. I believe all states have something similar. These services are designed to put supports into place to assist families who are trying to care for a loved one. Services such as: Personal Care, Respite, PERS (Personal Emergency Response System) can go a long way to providing the needed support. Contact your local DSS, or Health Department. They should be able to assist you. Individuals do need to meet financial and medical necessity criteria.

One of the reasons that I advocate for families seeking out paid professional services (ex. case management under the Elderly Waiver) is that if you are not familiar with the system, attempting to navigate your way around it when the need is "now" can be unbelievably stressful. Once the resources are found by the family, they then also have to be monitored ( emphasis on monitor). The reason I recommend case management services is that they are trained to: link, monitor, coordinate and advocate for the patient. When the child of an aging parent tries to take care of these aspects in addition to maintaining their own life, the toll can be great. I guess my bottom like is do not hesitate to ask, beg, scream for help...you will be doing yourself and your parents a great service.