How to help exhausted caregiver ?

I am writing on behalf of a dear friend I will call Susan, whose own physical abilities are challenged from horsebackriding injuries incurred as a young woman. Susan is single and continues to work a full time job with physical requirements that can be exhausting by day's end. Now that Susan is in her late 50's, she has become the sole caregiver for her Ukranian mother who suffered a stroke approx. 3+ years ago and cannot live alone. Susan has said that she and her mother have never been close, and although she has siblings, they are not nearby and do not help her with the challenge of caring for their mom.

Susan's ongoing day-to-day rollercoaster ride of emotions and difficulties can be hard to watch. Her mother is argumentative, doesn't like American food, has poor vision (hindering any entertainment possiblilties like TV, or reading)and is generally very unhappy. Mom does not leave the house all day, so when Susan arrives home after work, she's greeted by her now very cranky mother. Although Susan does her best to be understanding and supportive, the situation is wearing her down emotionally. Anytime I have suggested Susan seek help she reiterates that her mom is so deeply rooted in her Ukranian ways and unreceptive to change, that she just doesn't know where to look for help in our area.

I know there has to be someone, or an organization that can help caregivers in these situations. We both just want her mother to be happy and enjoy whatever years of her life are left. Please advise if you can. We are in Springfield, Missouri.