What do you look for in a carer/assistant?

Hi all,

I applied to a job as a carer for a young person with spinal injury who needs assistance in his day to day life. It's not something I have done before and I have no experience in it, so I wrote a cover letter explaining why I would choose it as a career path and why I should be employed by him. His recruitment manager seemed to be impressed with it and she's called me and asked me to an interview with him, which I'm so pleased with. Only, I could do with some advice before interview. I have worked in some high profile jobs in the past but find if I am not prepared enough at an interview I flop it out of nerves. I've been told the client is highly intelligent and social and is looking more at personality than experience (as obviously I would be sharing part of his life with him), but I'm sure he will ask me some questions to ensure I am competent.

What sort of questions would you typically ask a potential carer?
What would a client be looking for from me? - I have read the job description. Asking more characteristic-wise so I can make sure I am the right person for the job.
How can I ensure I am tactful when discussing his care?

I don't want to enter the career without a bit of research as I appreciate is an important job and I need to be the right person for the role. Some insight from yourselves would be really helpful. Although I have never considered care prior to this, I am really interested in the job. I have a young family member with similar mobility issues so it's close to my heart that I would be able to assist this person in living a full life. I also genuinely think he sounds brilliant so haven't applied thoughtlessly.

Any advice I'd appreciate greatly. Thank you for your time!