You're at a very tricky position.
Caregiving is a skill, and it's much needed in today's society. If you're wanting to care for your friend one or two nights per/week, you ought to be okay. If, however, you're wanting full-time work, this will create major struggles with obtaining SSI/SSDI.
The whole point of SSI/SSDI is to help those that can't handle working, and making a liveable income. You have to take these aspects into consideration. Be honest. Can you handle working nearly f/t with helping your friend in the evenings? If so, SSI/SSDI probably isn't the best road for you to take. And I would encourage you to take a class to make yourself a PCA (professional care attendant) to use later down the road. The pay is pretty darn good and always needed!
If you're thinking that this is just going to be easy money, caring for your disabled friend one or two nights a week, then give it a try and see how well you can handle it. *Just so you know, many nights go uneventfully. Others with chaos do come though and you have to have plans set to fall back upon when those hard times do pop up though.*
As an former CNA, (certified nursing assistant) I can attest to both the pleasure of helping others and the stressful needs/ demands that also come with the territory. Not a lot of people have the patience, compassion, and care to put their TLC into caring. It can be a wonderful experience!

But, it can also be very demanding and I couldn't keep up would those frequent necessary changes within the nursing home.
Think about it.