I have been thinking this over since my earlier response and was wondering…do you have any married sisters? What is your father’s relationship with them? If they have told you that your father is a good shver, then you have someone to model yourself after.
On the other hand, what is your father-in-laws relationship with you? If you feel he is a good shver, then you have someone to model yourself after.
Did you ever say to yourself, “I wish my shver didn’t treat me that way”? If the answer is yes then don’t treat your SIL in that manner.