That’s kinda like many of the Catholic members of my family, too. I can’t speak for how seriously your father takes his faith, but it might be worth pointing out this part of the Catechism:
1457 According to the Church’s command, "after having attained the age of discretion, each of the faithful is bound by an obligation faithfully to confess serious sins at least once a year." Anyone who is aware of having committed a mortal sin must not receive Holy Communion, even if he experiences deep contrition, without having first received sacramental absolution, unless he has a grave reason for receiving Communion and there is no possibility of going to confession. Children must go to the sacrament of Penance before receiving Holy Communion for the first time.
1458 Without being strictly necessary, confession of everyday faults (venial sins) is nevertheless strongly recommended by the Church. Indeed the regular confession of our venial sins helps us form our conscience, fight against evil tendencies, let ourselves be healed by Christ and progress in the life of the Spirit. By receiving more frequently through this sacrament the gift of the Father’s mercy, we are spurred to be merciful as he is merciful.
So, as Catholics we are supposed to go to Confession at least once a year. Also, even if he believes that he only has to go to confession for something like murder, it is highly recommended for lesser sins, as well.
I didn’t used to want to attend confession either, but when I learned to see it not as a burden but as a gift, it became a matter of my sins and when I wanted to go, not when I was supposed to go. It is a mercy, not a punishment. I hope that you can get him to understand that through your own good example! Good luck.