I'm assuming the dick has the urethra that the pee comes out of from the bladder. Females and males both have this tube for urine, but the tube runs in different locations(dick for men, and a hole above the vagina for women). If a female lost the vaginal opening they can still pee. Males have a special muscle in the penis since sperms and urine aren't produced in the same location to allow one or the other to pass. The character has no testicle for sperms production so no ejaculations from the penis, and I'm assuming the penis gotta let something out.
Therefore, the penis is only for pee, the vagina is connected to a womb and can cum, and the asshole is for poop.
You said people don’t pee out of their pussy… but they do! Girls do, so I don’t know what you’re talking about. That doesn’t make much sense to me. And in what universe does a specific gender have two genitals? That just sounds weird, and I’ve never heard of that before. But please, go on and keep explaining this 'basic anatomy' you seem to know so much about.
So, just one thing... Where does he pee from?