Normal for a ASD 3 year old. Don’t force- you will have a violent aggressive 5 year old. Make it funny (see a alligator in your mouth, monkey etc) Give choices- brush or something else he doesn’t want to do. Give lots of time and thousands of reminders. Don’t punish, again resentful 5 year old. With age it gets better but at 3 just hold on and pick your battles.

As for brushing teeth, let him hold the tooth brush, and put it in his mouth at first...then move to holding the tooth brush in front of him..but still let him have the control of brushing his own teeth ...it may just be him wanting control bc he feels like he doesn't have alot of it with his autism.

Washing hands may be harder bc it has running water, which is scary, and the water makes constant noise...but maybe run sink water next to sink already filled with water and maybe he will try putting his hands in it then?

I have these issus with my 4yo....Give him baths/showers when he is willing, in between that do pool time, and water rime...water rime at tge sink is our saving grace...we fill our sink up with soapy water and toys....we push a chair ( back of chair against counter for stability)...eventually my boy climbs in to it and its a make shift bath...i think he likes this bc its a conteolled/ small amout of water...and he feels safe.

Gentle persistence. Mine love to play in water on their own terms. Bath time goes pretty well intil the head gets wet. I just gave up on staying dry during the process and continuously reassured them. The boys now do baths without major drama, but my little one will stand in the hall crying and stimming at the sound of a bath being drawn.