It would help if we knew the reason why not the fire extinguisher. I'm aware that it's often house owners or other halves saying no to large, bright red things with warning labels on them.
Instead of a fire extinguisher you can get `proper` co2 cylinders, usually you pay a deposit and then just pay for refills. Do a Google search for suppliers in your area. Have a look at boc gases or search for hobby gas co2.
I got a cylinder from planted tanks in Selby and just pay 15 for refill every few months
Fire extinguishers are perfectly safe to use and are pretty much standard for planted tank enthusiasts
I'd get that. In your position the best bet it is to get the brand you like at the cheapest you can pay - It will be the only way to keep your Dad's mind at ease.
But in the broader sense, for when you're in charge - rest assured that there's no way on earth that people who use CO2 day to day would use something like JBL etc - They're goning to choose a brand that has something to do with pressurised gas equipment in the first place.....IMO
i know where your coming from about parents not letting you have a CO2 system... i had to run a DIY yeast one for my tank when i had it set up, a pain in the ass, id of loved a FE one... but they were touchy about a gas bottle in my room... but yeast and excel works ok