You could still give him a daily dewormer, but in most instances these cost more than they are worth and they increase the speed at which parasites in your area develop a resistance to the chemical dewormer in them. 50% of horses control parasite loads on their own with very little chemical assistance and only need to be dewormed twice a year. Even horses who don't have a good resistance to parasites only need to be dewormed 4 times a year. Plus there is resistance already to the pyrantels (the active ingredient in that product is pyrantel tartrate) is seen in 40+% of areas tested in the US.
You should really just assess your situation and determine how many times a year your horse really needs to be dewormed and stick to that. Weather conditions, management particulars--stall, paddock, pasture, feces removal, age of the horse,and your horse's own natural resistance all affect the amount of deworming that is really necessary.
I would recommend that you watch the deworming webinar on www.thehorse.com
. The equine parasitologist lays out a complete deworming plan and tells you how to figure out when your horse needs to be dewormed. The Horse | Videos