will the inside light of car, left on overnight , drain the battery significantly?

Yes wake him up.

Headlights left on for an hour will drain the battery.

4-ways left on for 3-4 hours will drain the battery.

inside lights left on for 7-8 hours will drain it enough to stop it from starting.

Give him a nudge and ask for the keys. Him hating you is less then the beating when it doesn't start in the morning.

If you don't need to drive your car immediately, get a battery charger with automatic voltage and current regulation, then charge the battery up slowly overnight (12h +) to avoid long-term battery cell deterioration from a quick charge. There are some expensive chargers as well that are quick and gentle at the same time with advanced electronics. A jump-start will get you going right away but the alternator would probably have to be running 12h or more to completely recharge a dead battery. The real problem is that after a jump-start you might be stranded somewhere else if the drive was too short and the battery did not get much of a charge.

I would wake him. You really don't know how long its actually been on. So its possible it will drain the battery.

Plus...people can see what's inside his car. If he has a nice stereo then someone might just break into it.

Also, its better to wake him up than him waking you up for a jump.

yes, i would wake him up before he has to walk to the store to bye a new heavy car battery. one time me and my dad had to walk 10 miles in a town we did not know because we left the light while we were at a hotel.

Leaving on the interior light for a few hours will make a dent in battery power but it should be OK.

it drain the battery and the car won't start by morning

Yes it can. Happened to me before. Wake him up. I'm sure if you left yours on, you'd thank someone for waking you up instead of waking up yourself to a dead battery.

Suggest if it is a fairly new battery,you may get away with it,if it is not,you could need a boost.

Yes, it can drain it all together. I have had that happen to me before.

if u live in compton u better wake him up!!! but if ur in a decent neighborhood and hes got time tommorow for a new battery or recharge then stfu