The likelihood of you hanging onto everything here is slim. You have to know that. Eventually you're going to have to face that the life they chose will come between you unless this is an extremely rare case.
Your dad could lose his position as could your mom. A lot depends on the overall attitude of their elder body. You can't apply the same rules across the board. If he's influential enough he might skate by, or decide to set a "good example".
We can't tell you anything for certain other than that at some point you will have to come out, be who you are, stand on your own two feet, and let them decide who they want to be and accept their decisions. You can't hide him or your fade forever. They get to decide how to react and you have to let them be then, and you need to be you. Let the chips fall where they may.
I'm so sorry about that.
On the other hand, you are free and congrats on the upcoming nuptials. Don't let them steal your joy. You're being prepared here for the likely inevitability.