Yes you did as much as you could and wre concerned ,sometimes parents are in Denial, they dont want to believe its anything they do wrong especialy the ones who dont get it.and being picked on is a favorite response it lets them off. You did okay.
I've been concerned for you, and watched for a return on the thread where we met at the start of this. Luckily I ran on this one; my mind is quite relieved.
You ask, "Did I turn my back on a desperate situation?
Is there something else I could have done? I fear that he will be passed on to another caregiver such as myself without his behavior being evaluated or treated."
You answer your own questions. You can't "turn your back" unless there was something you could do and didn't, and there wasn't. You made the best effort possible when you attempted to communicate with the mother instead of letting it go; if she is ever ready to admit and deal with her extremely serious problem (other than by a tragic incident) it will be not as a result of one person's taking the situation in hand--you can be sure people have tried, to no avail--but as a result of an accumulation of drips on her head. You contributed your drop, it's good that you did, and it was all you could have done.
From what you say in this recent post, apparently the aunt is an enabler, striving to keep reality at bay so the mother can stay in denial. If the aunt is mother's sister, this is likely to be a lifelong pattern, and anyone trying to change it (as you found out) will be the bad guy. And, of course, the boy will hear them talking about how the whole world is against him and nobody understands him and everyone but them is wrong--which, since he is already troubled, can be counted on to wreak havoc with any treatment program he may be placed in.
Yes, this boy will be handed off to another unsuspecting person like you. You weren't the first, either, by a long shot. Maybe the next time, or the next, when the caregiver is as responsible as you were in reporting the behaviors, it will be the last drip, and she will seek help. Or maybe his school will involve child protective services which, whatever their shortcomings, are about the only route by which the mother can be forced to deal.
Anyway, luv, you did good. Congratulations.
The more people who turn their back on her, luv, the more obvious it will become that she needs help. Sometimes it takes running out of child care providers to wake parents up - you see that all the time. They describe a horrible child, and their overriding concern is they are afraid the child will be kicked out of day care.
You did the right thing. As more and more babysitters refuse to take care of him, she will be forced to seek help, so she can keep leaving him with other people.
Sad motivation. But still, a motivation.