well they'll know who to come to when their drums finally fall apart

They're gonners. There's only a certain amount of things you can do by ear. Unfortunately, my brother's tuner has a broken mic and my guitar is an acoustic guitar.

Does one not tune drums by ear? If not, can you recommend a good drum tuner? (or can an electric guitar tuner be used?)

you can't learn to tune by ear without resources, and the correct ones. i learned the hard way correct sources equals valid quality.

I don't think you're really understanding what drum tuning actually is, as a whole.
You don't really need to tune drums to specific keys unless it actually plays a part in the music. The main thing about tuning is tuning each top and bottom skin so that they resonate sympathetically with each other and the size of the drum itself. When you're doing this, you can do it by ear because you're not going for a particular key.

For example, let's say you're tuning one of the wing toms. Let's say it's 10" wide by 12" deep. That particular size is going to have a particular resonance, decay, etc. Say you start with the resonant head (bottom head), loosen it up until it's flappy. Then, turning each lug opposite one another, get the head EVENLY tight until it begins to produce a tone when you tap on it.
Now flip the drum over and do the same to the batter head (top head). When you're there, flip it back over to the resonant side and begin tightening and tapping near each of the lug points. You'll know if they're unevenly tightened because there will be differences in the tone. Just go a single turn on each lug, adjusting the turns so that all the lugs produce the same exact tone near each of the lug points. When you achieve that, flip it back over to the batter side and do the same thing and achieve the same tone as the resonant side. When you achieve this, pick the drum up into the air and hit the batter side with your stick. Does it have a long, smooth sustain and resonance? If not, you need to either tune both sides higher or lower. There are "zones" you'll hit, but it's pretty easy to hit the right one because the right zone is where the heads are pliable, not too tight, not too loose, and you get a lot of sustain and it sounds EVEN. As in, no warbling ring. Just smooth tone.
If you get that right, you have tuned the heads correctly to the drum. If you want to sacrifice some sustain just so you can have the drum in a specific key for some weird reason, you can go up or down on both sides EVENLY... but I just gotta warn you, if you tune to keys instead of the drum itself, you're probably going to end up sounding like you're playing a stack of boxes.
Correct drum tuning means that you adjust the heads so that the heads work together and with the fundamental note of the drum, as dictated by its size and accommodation of the vibrations being produced inside it.
This isn't just music theory, it's physics.

Thanks for the info! :)

From what I've read, each drum should be tuned to a different specific key, but not just whatever one you want. What you just instructed would produce a key from the drum, but whether it's actually in perfect key is important (whether it's C/Cb and not half way in between); is this correct?

Well, the important thing is that the drum is "in tune with itself". If the end result is that it turns out the drum is tuned dead on to a C or F or whatever, then great. But the note isn't the important part.
The size and depth of the drum is going to dictate its fundamental note. You don't need a tuner to find out what note it is. Just tune the heads properly and use your ears to find the zone. That will be the note of the drum. If you want to nudge it up a little if it turns out that note is flat or something, sure.. go ahead. But don't arbitrarily always tune the first tom to a certain key, the second, third, etc. Tune the drum to itself. After that, see how you like it. I bet no one will call you out and say "HEY, DRUMMER... I NOTICED YOUR SECOND TOM IS HALF A CENT FLAT OF E!"

So it would be best to tune the drum with itself, to a note that sounds best, and than use a tuner to see what note it actually is so that tuning the same drum next time around will be accurate? What I'm looking for is consistency, I know drums can only do so much and aren't intended to always have a perfect tune like guitars.

My brothers' problem is probably their inability to hear for any particular note each tuning.

freebase, you are a spot-on kinda guy, huh?!

tuning the drum to itself will give you all the consistency you need, jake. you don't need a tuner, because your ear will develop a taste for a properly tuned drum.

Freebase pretty much summed it up.

Although I have seen in some post-hardcore/metalcore bands (or any band that uses breakdowns), drummers tune their bass drum to the open C (or Db, B) or whatever to match the low string on the bass guitar. Makes a breakdown, or any segment of the song where guitarists and bassists are all playing an open note sound heavy as ****. But unless you're going for that type of sound, or playing all your songs in the same key, that's not going to do you a whole lot of good.