I am potty training 3 year old son. is it ok for him to watch me pee standing up to learn how to go that way or should he just pee sitting down for now? i am his father.

Works fine: Demonstration is one of the primary ways you teach. It works well for some but be flexible. Some 3 yo who spent years peeing in a diaper may feel pressed to try something new.Squatting to poop & changing to pee is also confusing to some. If you know of a simple reward like computer time or videos to use as an inducement he may be more willing to try.