I don't think preventative deworming for a snake is a good idea. It's stressful for the snake- getting a tube put into the stomach. Mine needed four treatments to kill all the worms. There's always a risk of damaging something during the process. Out of the four snakes I've just had dewormed, I only had one injury- that was when Zee bit his tongue during the process- but still. Plus you need an acurate weekly weight to calculate the doseage- it's not as simple as horses or even dogs and cats- because snakes are so much smaller, it has to be more accurate.
I'd get your snake dewormed- and good luck with the coccidia- that's tough to get rid of, and in birds, they always carry a small amount- it's just when other bacteria gets out of whack that the coccidia can multiply. Then check the fecal after the deworming, and then again in six months or a year. If they haven't picked up anything then- :shrugs:
Nanci