BBQ_Pork...to filter out virus, you need to exclude a diameter down to about .02 micron, .1 micron for the larger bacteria ...for heavy metals and city chlorine, there are some surface bonding resin strata and activated charcoal filters available (which I assume Brita is), but they will need periodic replacing....

I chose to use a Sawyer filter (5 gal kit with the .1 micron filter) for my hurricane supplies, that can be back flushed and is good for a million gallons...and plan on using a chlorine based purifier anyway, so went with the cheaper .1 versus the .02 filter... I built a DIY vertical PVC column that I filled with aquarium grade activated charcoal, but haven't tasted it yet...

what exactly is your Dad wanting to use the filter for? good tasting water, or emergency water?