yep, you can go to southern states and get a decent dog wormer. they're pretty gentle and it's hard to overdose them on those, and they usually kill roundworms. if he had fleas in the summer he will need something for killing tapeworms (these kinds you can see evidence of in the poo or on the butt), but if he has hooks or whips (which you CAN'T see), you'll need some panacur (anthelecide - sp?) you can use the horse paste on dogs, but you only give a SMALL amount, according to their weight, and give it for 3 days in a row (it's ikky tasting), wait 2 weeks and do it again. That stuff is EXPENSIVE from the vet but it will kill all sort of wigglies in there.
BUT.....if you get him the monthly heart worm meds from the vet, this will take care of them all except hooks and whips. BTW heart worm meds can be given BI-monthly and still be efficient. A cardiologist told me that. It kills the difilaria, and that can be done every other month and still be safe since the difilaria lifestage is a month or six weeks.
Save yourselves some $$ folks!!