I gave up trying to make my DS do everything that everyone else was doing and saved my sanity. Seriously, I just stopped fighting him all the time. Expecting him to comply just because I asked or demanded was not going to happen.
DS did not speak until 18 months and would not talk to anyone but me or dd until almost 3, and then only in complete sentences. By 3, I was at my wits end too and started getting down at eye level to explain, explain, and explain again what my expectations were. I didn't make him do stuff but I did make him understand what was expected. I did this for two years straight, consistently, in good times and bad (there were both). It was exhausting.
I bought him shoes with no laces. I served him deconstructed meals (same foods as the rest of us just not touching). When his kindy teacher told me she couldn't assess his reading because he wouldn't speak, I explained TO HIM that his teachers don't know what he can do because he won't talk. His response, "You mean, they think I'm stupid?!" Why yes, son, they do. By the end of the week, I was getting love notes about his sense of humor and academic abilities.
He needed the time/space to mature emotionally. He needed adults to talk with him not to him or about him and explain the reasoning for X Y, or Z. Then, and only then, did X, Y Z make sense for him to do. He is a control freak!
FWIW, my DS learned to tie his shoes just two months ago in a 15 minute session with DH, not me. Apparently my bunny ear technique was too 'juvenile'. It's hard to be patient and rely on words with such a child but it did work for us. It is also an ongoing struggle.
I wish I could say it was easy to get this child to take on challenges, even now, but it's not. If he cannot do it perfectly, he will not try. When he finally does deign to try it's like HOLY CRAP, where did that come from? He blows people away. It's just who he is. I'm just not worried anymore.
Honestly, I can't decide if he's conditioned me to accept less from him than he's capable of or I've learned to accept his idiosyncrasies.