Grooms father

Let him wear whatever he wants. Presumably he is an adult and can dress himself.

Grooms dad and both my father and step dad are wearing whatever they want

Our Fathers are wearing the same tuxes as the groomsmen

They should dress to the same degree of formality but it doesn't have to be a tuxedo. A dark suit is fine for an evening wedding (which I presume you are having if the groom and groomsmen are wearing a tuxedo.)

Here it's tradition to include the fathers in similar dress to the groomsmen. We rented formal suits for all the guys including the fathers. But that's tradition here. I would say it is completely up to you. I always liked the idea of including them though as they are important.ETD we also included grooms stepfather in the suits as he is close to DH.

Whatever they want, my fh father is renting a tux just the the wedding party and my father because he wanted to match

Whatever they want.

My father in law rented the same tuxedo as the groom and men in the bridal party. My father wore his own tuxedo - plain black, but didn't match, that he got for 50% off at Men's Wearhouse.

FBIL and my dad are both wearing black suits. FH and my son will be wearing matching suits.

My dad is dressing to the same degree, just in a different color coat. I have absolutely no idea what my FFIL and FSFIL are wearing.

Our dads wore whatever they wanted.