I’ve been looking at the cannon rebel t6i package which runs around $750-$800.

Honestly, that's a tad bit pricy for the t6i. (Unless that is with 2+ lenses).

Not bad for everything I think I’d need including multiple lenses, sd cards, carrying case etc.

Most of the bundled items will be crap.

However I talked to one of my friends who’s a professional photographer and shoots multiple weddings weekly and he told me that I should not get the rebel. Reasons being that supposedly they need to be upgraded every couple years.

That's only true if you're shooting thousands of pictures a week (which he is).

Even sensors from 10 years ago are still pretty good for casual use (and there are diminishing returns on further upgrades).

He recommended that I buy a professional camera instead because they’re more durable and it will save me a lot of money in the long run.

Not really.

For the price of one D500, you can get a t6i and two replacement bodies in the future.

It'll last longer, but it won't save you money.

Now since I’ve never shot before and this is just for fun as a hobby I’m not sure I can justify spending $1K+ for just the body of something along the lines of a 80D. If what he says holds to be true though then I suppose I’ll just bite the bullet.

What do people think? I mean I could spend $1200 and get an 80D with the lens he recommended (50mm 1.8) or buy the rebel t6i for $800 that comes with everything.

The 50mm f/1.8 STM (not the older 50 mm f/1.8 lenses) is a great purchase at $100. I highly recommend it if you go with Canon.

A t6i or T7i (or an A6000, G85, E-M10 III, X-T20, or D3400) would be a better option for a beginner though.

It doesn't have the extra pro features, but it does what you need for much cheaper.