Are Khan academy practice questions representative of actual SAT?

My son has started his SAT prep and took his first full practice actual SAT this past weekend. For the two weeks prior he took practice sections on suggested subjects based on his sophomore PSAT. He is taking detailed notes on each math question he missed on the full SAT. Question is should he be doing that on the practice sections as well? Frankly, it is a lot of work and I want to make sure it is worthwhile as I was told by a friend that the practice questions are not formulated by the collegeboard and to focus on the questions from the actual SAT. Right now he reviews each question to make sure he understands it then moves on. Thanks for any guidance.

The math questions are pretty accurate to what I saw on the test. However for reading I think you’d be better off watching a video and using an actual test from the collegeboard website to practice from. I like to use CrackSat you should probably check that out