I work in a care home so i'll tell you what my interview was like and hopefully that will help you.
I didn't have any care experience when I applied for the post. I want to become a Nurse so that was my motivation for applying.
I went in for my interview and had to fill an application form in as I had sent my CV to the email provided in the ad. So I was sat for 10 minutes filling that in. I would bring your CV with you in case you need to refer to your contact info, or if you don't have a CV make sure you bring your contact and reference info with you in case they need that.
After I filled in the form I was taken into the managers office and he interviewed me whilst another member of staff took notes. He first asked me to tell him about myself, so try to keep that short and sweet but include something that relates to your suitability for the role, for example the fact you are a parent.
Some questions I remember:
Why do you think you would be good at this role?
What are the most important skills a care worker needs?
How will you protect client dignity and privacy?
What have you done previously that makes you a good fit for the job?
How do you work in a team/on your own?
Now I got the call and attended the interview within a few hours of each other so I didn't have time to prepare AT ALL. However I still got the job despite a few fumbles on questions. I would look at any job vacancies online for care roles and look at the job specs and the type of candidate they are looking for. Prepare a list that demonstrates why you fill each of these things. It doesn't need to come from job experience, it can be anything. Keep the list on you and refresh yourself before the interview so you can pull from it when you answer questions.
Don't worry that you haven't had a job. They already know your work history and they still invited you to interview. Generally the interview is to make sure you are a nice person and a good fit for the company. So just relax and be confident!
Also go in interview clothes
Oh and be prepared to meet the CRB cost because not all companies will pay for it.
Good luck!!