The HERO Initiative aids comics professionals who have worked for the Big Two as creators, and in comics for at least ten years. The Comic Book Legal Defense fund defends first amendment cases.
A lot of people don't understand this, so there it is.
 

Most important thing: MONEY. Insurance can be bitchy and pokey. Immediate cash for clothes, food and so on is a HUGE help. It gives a sense of security.
More on money and contributions further on.

Unless you've lost a house in a fire (or other disaster), you really don't know what it's like. You're right, you can't imagine. "Sucks" doesn't even thinly cover what it's like to lose one's home in a fire.
From my own experience, expressions of good thoughts and encouragement were enough. You don't have to try and relate. It's cool to just say, "I am thinking about you, and wish you luck."

The best way to understand the loss of one's home (at least as much as one can without losing their home to a disaster) is to imagine going into a Target (for example) and understanding that even if you bought one of everything, from the craziest to the most useful, you would not duplicate a single thing. Then imagine that you have no place to put it.
And that's still not enough.
It was weird to realize, after our house was gone, we didn't have measuring cups, drinking glasses or a can opener. Band-Aids. Pot holders. Towels. Underwear. Shoes.

We had overwhelm in spades. It was hard to answer questions, let alone make plans, lists or eat. If you ask someone what they need, don't be offended if they can't answer (send money), don't be surprised if it's something weird. When GuruEfx point men Joe Weltjens and Lee Duhig came to our house the day it burnt down, we had them drive us to a local vet and we...adopted a cat.

PayPal looks very hard at accounts set up as charities, and will close them. (I know, they closed mine for 24 awful hours.) Best to PayPal Lance and/or Carla directly if they have PayPal accounts as note the amounts as a "gift" rather than "donation." Pretty much anything BUT "donation."

For fuck's sake, DON'T do a charity book. By the time you corral contributors, et the book assembled, pay expenses, get paid, you've given yourself a HUGE headache and probably a lot less money than you intended to send. Benefit books also tend to result in hurt feelings.
A live benefit, or eBay auctions, OTOH, are good.   

Don't send anything not asked for (unless you happen to know the person very well.) People who lose homes in fires (floods, quakes, storms)  will have storage issues for maybe a long time. This includes managing clothes.
When you send something, send something you'd like to get. Don't pass along the equivalent of pickled beets.

Send money. If you can't (and that is totally okay), send a note, or pass along info.