Throwaway for obvious reasons...

I’ve got a good friend who is in the same industry as me. They are self-employed, and have a small business. They do ok, not great, and often have annoyed customers because they are slow albeit good at what they do.

The situation:

- this person recently became quite ill and needs time to recover. 
- being self employed, they had no insurance and are drowning under bills and can’t afford to lose customers
- they asked me to help some of their customers while they’re recovering

The problem:

- they have left many of these people hanging for weeks without communication, and sent no real notes on the job to be done, just forwarded emails, meaning it’s a lot of work to figure each one out
- they told these people I work for them, so the customers are directing their rage at me

I want to tell this person that I can’t clean up the messes, only deliver the services. I have a full time job and kids and don’t have time to run their business too but i feel like an asshole for pushing back and saying this wasn’t what I agreed to. I know they are in a desperate situation. 

Am I the asshole?