We are dealing with similar behavior, althoug I can't tell if there are any good moments in your description. Our son is generally a great kid, smart, eager to learn, very active. He just wants things HIS way, when HE wants them, and he goes into full meltdown when you redirect him from unacceptable behavior. This pattern comes & goes and is unpredictable but seems to be really the worst when there's a significant change in routine or structure. And once we're in a mode of negative behavior and negative discipline, it's hard to get back on track toward anything positive. It sounds like your son has a LOT to deal with - new family, new siblings, probably new place to live, maybe even kindergarten soon? Wow. And no Mom stability makes it even harder.
We're trying a few different things, but the most successful so far have been:
- have your behavior chart track smaller time periods - a DAY is too long for a 5 year old to remember what 8-9AM was like vs. 2-3pm good vs. bad. Talk after each hour about what it felt like to make good choices, and what it felt like to make bad choices and have consequences. Try to "reset" the new period of time with a deep breath and a smile, and that you know he is trying hard and that he can make good choices. Tell him what good behaviors you expect. Be specific. Provide some opportunities for him to earn his toys back. Overly praise him when he meets those rewards.
- Try to keep your every day routine the same as much as possible. This includes wake up times, the routine to get ready, mealtimes, times of high energy activity, quiet times, how you manage transitions, when you have 1:1 time, and what you do to wrap up your day for bedtime. Create a consistent list of family rules that everyone has to stick to. Create a set of consequences that are meaningful that everyone has to stick to. Have a family meeting where everyone in the family understands the rules - what TO DO, and what NOT TO DO, rewards and consequences, and scheduled routine. Write it down, Hang it on your wall, make everyone sign it (sounds crazy, but it helps to have an agreement that you can refer to); Be consistent about enforcing the rules.
- Read the book :Parenting the Strong Willed Child by Forehand and Long. The first skill they teach has had the biggest impact for us. It's called "Attending" where you provide a running commentary of what your child is doing, particularly focusing on the positive aspects of what they're doing. Attending provides your child attention to good behaviors, AND it provides a "reset" for your relationship, especially if lately you've started to only notice negative behavior. Not every moment is negative and attending helps you at least get back to neutral, and maybe positive. I've found that I can stop a meltdown in progress just by changing the mood by neutrally describing what he's doing.
- Also, read: How to talk so your kids will listen and listen so your kids will talk. The book goes through multiple skills that help create empathy with your child, give positive attention to reinforce good behavior, provide expectations for them to meet (in a good way).
These books are relatively easy to read a chapter per night and put some of the tips into practice the next day. I think even the first chapters in each book are the most helpful.
As an aside: I think it's weird that your kids have special food that is theirs and theirs alone. Is it like one person's oreos stashed somewhere, and another person stealing someone else's treats? Sounds like just another source of conflict, and something that adults can manage when they are unrelated roommates - not in a family with kids. Do you want your common household to really function like a family? I believe that a family should be a bit like a commune of shared responsibilities and shared resources. A family should have common food that is provided at specific mealtimes and snack times by the parents. And common healthy snacks for everyone (fruit, string cheese, veggies). Your house rules should include respect and care for everyone's things and feelings, but the system you describe seems really hard for kids to understand and follow.
ETA: the food thing makes a little more sense now, but again, I think a 5 year old has little self control for that kind of thing. Pretty hard for him to understand that at the movie he got some, and now it's gone.
Does your school have a counselor, and does your son have the same behavior at school? Our school counselor and his teacher have been really helpful at partnering with us for consistency on messaging, and techniques that are working or not successful. They provide us daily feedback on how things are going, and are helping us to identify triggers.
I would pursue getting the school to work with you, and your school should help you identify what you need to ask your doctor or refer you to a psychologist. They are trained to look for learning disabilities or challenges getting in the way of learning. And they see hundreds of kids every day. I would call your doctor and describe exactly what you've asked us. Try to document some trends and patterns, and try what has been suggested. If it hasn't been successful, then the doctor/psych will already know what you've tried for behavioral changes.