Keep in mind that expenses should always include the expense of vet care, if and when you need them. Most reptile owners I have met neglect to add that in their budget, especially the new owners. Low and behold, someone brings in their beardie who had stopped eating due to impaction, and the new owner never considered of wanting to or having the money for medical care. I always tell people no matter the species of pet, the upfront costs is only a small fraction of what you will spend plus what you should prepare yourself to spend if an emergency comes up.
With that said, I have family who also do not like snakes like your dad. It is a common theme among us keepers but that is okay. I would tell your dad but don't push it. I always tell strangers and friends and family alike that I have snakes. I leave it up to them to ask me more about them. If they don't, cool. If they do, that is good too. I don't like keeping tarantula as pets (though my husband does and I don't mind them) but I would be annoyed if my husband or others try to convince me otherwise if I just am not interested.