First, welcome to the forum! Stick around, join the conversation and read older threads (tags on the bottom help with searching topics) We area friendly and helpful bunch!
Second, the first rule of sanity for me was to never put more effort into training a child to do anything if the parents are not working with you.
In your case, the parents are nice and while that is great it bears no weight in the fact that they are happy and content and oblivious to the work you are doing with their child.
This is abundantly clear when you have to re do everything after a weekend etc. They are more than likely not seeing things the way you do and probably not being honest with you at all. The baby's behavior tells you that.
I understand this infant being your only income but have you thought about finding another infant to take instead.
I was exhausted reading your thread and all the work you put into this baby...NOT that it's a bad thing...I am sure you were a godsend for this little guy but it's a smart business move and a sanity saver to recognize right up front that you are not responsible for fixing anyone's child.
It should be parent first, extended family and friends and then provider...there to support and assist but not parent FOR them.
Not all babies are like the one you have but sadly most parents are. Most will happily let you do all the hard work and not consider how stressful or hard it is for you.
You will be caring for a GROUP of kids. That means each deserves attention and when one child takes more than their fair share, you'll have trouble. As well as tons of stress.
Figuring out how to balance your role and the parent's role is key to maintaining your sanity in this profession.
