Looks like it's actually cheaper at $9000, but the profits are nowhere near that. That's got nothing to do with this thread though.
SLI is overrated, the performance gain is not worth the price.
What kind of monitor is he using? Or is he buying a new one?
Unless he's doing 4k@100hz or something even crazier, he really doesn't need anything better than a 1080 Ti.
The setup
@viral777 suggested is plenty for gaming at 4K or high refresh rate (but probably not both)
Maybe put some more RAM in in the future (so get 2x8GB sticks now and leave 2 slots free assuming the mobo has 4 slots) but currently RAM is overpriced so there's no point in filling up all the slots right away. You could even get away with a single 8GB stick for now, which should be enough for gaming, but 16GB minimum is suggested for multitasking.
i9 is worse for gaming than an i7.
I always say this, but getting the very top-end components comes with a hefty price premium, at only a slightly better performance than the components just below that. So it's best not to go all-out right away and instead save some money for upgrades later on.
That being said computer hardware is really expensive right now so $2000 actually doesn't get you a whole lot.... might be best to wait a little.
Ryzen is worse for gaming.