LOL, is your BF ____ ? my brother's GF, who along with DB stayed with us for a week year for holidays.... and said the same about my then just 4 yo (now 4.5).
I felt so bad, and talked with DH, over and over, about how I was failing my kids..... They would grow up a mess..... etc.
YK, I had already known that ds1 doesn't do as well at home when we have stay over night company. Those added emotions and people disturb our family millieu.
but when we have company for a dinner, he's perfect. Quiet, polite, sits up ramrod straight in his chair (and I have not yet ever corrected his posture), eats his whole dinner.
A couple weeks prior to that I had brought him to a design showroom. As I went from suite to suite, he was perfectly behaved for 3 hours.
But to answer your question.... depends on the day. Yesterday, maybe 1 meltdown lasting 3 sentences. Today..... maybe every 15 min. To the point that dh and I both did our LION cry " EEEENNOUGHHHHH!" on at least 2 occasions. Fortunately, my hand did not fly.
At the last parent conference of the year, ds1's Montessori teacher said she wasn't sure "what" was going on, since ds started to refuse to cooperate sometimes. In response to requests for circle time, or clean up, his response was a nonchalant "NO."
My response was nothing was "going on," except that now after 8 mo, he is finally comfortable enough with his teacher to be himself.
Kids are .... well, kids. Uncultured, impulsive, rambunctious. I think it takes a lifetime of learning, culture, society, and teaching .... to turn out a well controlled, even tempered person.
For many years, I practiced primary care medicine. Most every person has some degree of crazy. Really.
The ones that don't look like it, like that well groomed, perfectly composed mom in your kid's Montessori? She is probably the worst. Just hides it well. Or is on meds. Or both.
America is full of overweight adults. People in debt. People divorced. Or in bad relationships. Or in affairs. Why do some women find themselves in one bad relationship after another?
B/c people make mistakes. They can't control themselves. Can't control their emotions. Can't control their budget. Their desires. Their appetite.
Doesn't matter if you are super smart. Or President of the US. Or governor.
My point is that... I personally (fwiw) think your kid is normal. Presumably: he's growing, he has some friends, he can play (even sometimes) with his sister, sometimes remembers to clean up after himself.
Becoming perfect (LOL!) takes a lifetime.
Why do we expect so much of kids in America?
I know I am not perfect (oh oh oh, far from it). My kids certainly are helping me (in accelerated form) become more of the person I ought to be. Meanwhile, my job is to help them become ...... ______ well, they'll fill in the blank.
goodness knows, wouldn't be fabulous if it only took 4 years.