I sure wish you were closer my son and hubby would help . Dogs who are terrifed of men just warm up to my guys in nothing flat.
We love springers like crazy here .
If you have an artist freind who is male artists think differently than others and it seems they give off a different vibe than regular men . I know it sounds crazy but I have seen it becouse of my to guys are artists . Had a rotti who had been beaten by 3 men in the relationship with the women who would get her. Saw her cower from the kennel guy (who she knew ) she ran full force in to my hubby's lap and she became his dog.
In no time she came to be comfortable with other men but not trusting of them . It will take a lot of patience and work, when you do get your dad to try make sure he shows no fear or she'll pick up on it. Good luck.