First, keep in mind that they are likely going to have PTSD. No matter how "together" they look, sound, etc., their brain is processing information differently than it was just days before. Give them leeway to say/do/not do things that might seem odd.

Some deal with stress by crying. Others with humor. Others just hold it in. This may not be how you deal with stress, but recognize it is how they deal with stress. Don't expect people to process things the same way you might. Let them process in their own way and support them in their process.

Don't say "at least everyone made it out safely." Their lives have just been completely turned upside down and while there is no question that human life is more important than material things, when someone who still has everything points that out, it can seem hollow.

Don't try to analyze/ascribe the cause (climate change, forest management, arson, reveals, etc.). They are in survival mode. There's nothing they can do about the cause now. There will be lots of time to analyze why fires happen, there's only a short time to show empathy for those affected.

Don't say "well at least you can rebuild" or "are you going to rebuild?" They are worried about where they are going to stay for the next night, week, month. They have so many more immediate decisions that need making.

Do say "I can't imagine what you must be going through." This lets the person know you recognize that their experience is deeply personal.

Do say "how can I help?" Then, if you're in a position to do so, make some suggestions. May I bring you fresh clothes? May I go shopping for you? Is there anything in particular you'd like to eat? They may not know what they need/want until you mention it.

If you're able to donate items, here are some suggestions.

Cash (non-store specific gift cards) is king. Everyone is going to need different things and cash can be used to get what they need. Keep in mind they are likely to have limited space to put things in the near future and don't need extraneous stuff.

New clothes or used clothes in great condition. Don't use this as a time to get rid of all those old ratty clothes you don't know what to do with. While people are genuinely thankful for whatever they get, it can also make them feel even more desperate/depressed to have to wear worn out hand-me-downs.

Socks, underwear, bras. These are likely things that people didn't grab.

Toiletries: soap, deodorant, toothbrush, toothpaste, lotion, combs, brushes, hair ties, towels, etc.

Canned food that doesn't need to be reheated (self-opening is best, but can openers are helpful too).

Granola/energy bars, healthy snacks, if it's going to be delivered soon, fresh fruit.

If they are a good friend and you know their tastes well, offer to go shopping for them (or, if you know them really well, just do it). For many, the thought of a new wardrobe is a thrill. But for someone who has just lost everything, shopping can be a chore. They don't want new clothes. They want THEIR clothes. Almost everything will be a reminder of things they've lost. Pick out clothing, toiletries, bath soaps, nail clippers, etc. Not having to make these decisions will be a huge relief for them.

Do be a shoulder to cry on. Tears are going to come easily and unexpectedly. One minute they will be fine, the next not so much. Normal, everyday things will set them off. Don't try to fix it, you can't. They don't need you to have answers, they know there are none. They need people who will let them grieve in their own way and on their own timetable.

Do offer thoughts and prayers. Whether it's an email, card, text, phone call, let them know you are thinking about them. One of the things my family mentioned as a strength getting through their ordeal was knowing that people (even those they didn't personally know) were rooting for them, praying for them, thinking of them. If you're donating cash or gift cards, take a moment and write a note of encouragement and stick with the card/cash. Let them feel the connection from a human behind the gift.