Flat head borer worms got to it and rotted the internal structure causing it to fail. Luckily, the still alive branches have braced it against the roof and my dad tied the trunk up with rope. However, I heard the plywood underneath the large branch snap, so I don’t know how much longer it will hold. The tree guys will be there tomorrow to check it out. My guess is removal will happen on Monday.

Ouch! Hopefully the damages won't cost an arm and a leg. That oak tree wasn't very old, either.

Nightmare!, especially with oak!, their heavy and probably the worst tree to have it happen with!
Was it just the worms, or was it also assisted by storm winds?, sounds like there’s only minimal damage which is a good thing 

There was no wind when the tree fell. It simply fell on its own from a rotted trunk.

Ouch I hope all is well and hope to recover from this damage.

I hope the damages are as minimal as possible!

We had someone else's tree fall on the property of our previous home, caused a lot of damage, and I was very upset to find that if someone else's tree damages your property, the owner of the tree is not responsible. I think that is the most ridiculous rule ever.

When we bought our new home, I cut down all trees within falling reach of our home. Then I had locates called on my property and I rented an excavator and removed all of the root balls.

I do miss the trees, but we just had a big windstorm 5 weeks ago and my neighbor's home was damaged by his neighbor's tree falling onto it. It SUCKS to try and find a tree crew to cut a tree off of your home right after a wind storm.

Without the trees our AC bill is slightly higher too. Better than any nasty surprises!

Was the tree still alive or dead before it fell?

It was still alive.

I had a large tree taken down by a storm a couple years ago...it fell in a neighbors yard. Made for some nice firewood.
My sister had a neighbors (dead) tree fall on her house this year in a storm. Luckily damage was minor.

Update: As of Jan 3rd, the tree has been removed. It was a 50 year old water oak tree, which is right about what the lifetime of a water oak tree is (50 years). The stump is irregular and misshapen, and there are holes in it from where the borer worms bored into the tree. The roof has sustained some damage. The roofers are coming on Thursday (Jan 6th).

Update 2: The roofer inspected the damage today. He is coming back tomorrow to fix it. I can finally put this behind me after that.

Yikes, i have photos somewhere when i had a ~200 foot tall tree fall on my house in california. Fortunately all that was damaged was the gutter on the house and causing a mess on the porch. If it feel at a different angle, it could have taken out the whole front of the house.