As someone said before in the comments, your father wants the best for you and he does not understand the issue you have. My brother is the complete opposite of me tall, amazing speech (Gave speeches in stages), doing well in life so you would think he too would not understand, but he does and he supports me in some areas when I tell him that I won't be able to speak he wouldn't hesitate to step up but he too does sometimes would not help or force me into a situation where I would have to figure out a way to get it done. Bottom line, other people who don't have a stutter won't understand this speech impediment very well so work on yourself and maybe tell him that it doesn't work like that (about you focusing well enough).