Hard start, lots of smoke, ~3 quarts low

Hey all, My sister has a 2013 sequoia. I'm a first gen tundra guy, figured I could ask this question here.
This weekend her Sequoia suddently had a really hard time starting. Took a few cranks & then it blew out a bunch of smoke. It turns out she was 2-3 quarts low on oil.
I've told her she's due for a timing belt change, I don't know if this could cause any of this issue?

My guess is worn rings. Is there a way to try to service this easily? What else could be causing her to be a few quarts low & hard starting?

 

Is it a 5.7? No timing belt on that motor.

https://www.motortrend.com/cars/toyota/sequoia/2013/

based on that the only engine 2013 up is the 5.7.

 

Given it was 3 quarts low, what’s the maintenance history? How many miles on the truck and what was the oil change interval? Once the smoke cleared did it run normal?

 

My sister bought it maybe 15-25k ago. I don't personally know the service history much. But I know she's not a car nut & her husband is lazy.
I'm going to run a bit of sea foam through the intake til it dies. Let it sit a bit. I would love to pour a bit down her spark plug holes & let it sit but I don't have that much time.
I'll just run the sea foam through it, put a bit in the engine and tell her to change her oil soon. Check it at every gas fill up & change it ever 5k.
It did run normal. It's just so rare to hear a toyota struggle to start.

 

When you say struggle to start describe more.

 

What’s her battery situation looking like?

 

It struggled to start in that it made the sound of wanting to start, but hesitating. Like it was either lean or rich on fuel. Took 2-3x the amount of turns to start. When it finally started, it puffed out a bunch of white smoke. Didn't smell like oil or coolant.
I don't know the battery situation. I'll check it out next time.

 

If the smoke didn't smell like oil or coolant and it was white my money is on fuel-related issue. Thus the hard start; too much unburned fuel.The low oil level is unrelated and just coincidental. Oil-related smoke is actually a bluish-white and will smell like oil.

 

I would start with checking the batteries health condition an then moving to check each spark plug