Help issue with water in oil and turbo

That sucks. But now you have to stop the downward spiral. Are you a young guy? With lots of money?

Your first mistake was writing to this forum AFTER you blew it up.
Your second mistake will happen when you just change the gaskets with the engine in the car, button it up, and go for your next test drive.

Make the right friends. Listen to their advice. Pull the engine. Go through the whole damned thing. Get to know it intimately. Have it rebuilt. Get an education in Turbo Buick. It's a long process. Make a choice. Your in this for the long haul. Or do what the plain old hot-rodders do. Get something with a small block, distributor and carb.
Sadly you are now officially a Turbo Buick veteran.

You have a choice to make. Unload it for cheap or spend a fortune.
Best to drop it off to a shop that knows what there looking at with these things there’s a bunch of stuff that needs to be in line to make them live and if your new to the game well...... you just found out!
I heard a pop but didnt think much of it.
It's important that you get the oil clean. Antifreeze in the oil isn't bad per say,but letting the antifreeze separate from the oil will result in antifreeze at the bottom of the oil pan and oil at the top. When you start the engine after allowing the oil and coolant to separate,antifreeze will be pumped to the bearings. This is when you will harm the bearings.

Were you at WOT when it popped?