Volunteer. Wear incredibly conspicuous attire. The question regarding if the house is going to be sold will be asked.  You get to ask, 'Have you ever heard of a real estate agent doing this for the home onwer?"

Have Masks available....you know about the value of FREEBIES...especially when worn instantly.

You can not have too much sanitizer in such an environment.

Present strategies to sell stuff in bundles. I like the 'everything in the box for $5."

You should suggest a raffle/drawing every 30 minutes.  Name, addr, tele. (Need not be present to win.) You may even choose to provide the raffled items so as not to stimulate the heirs.

The family you are helping may appreicate a stess free sale so maybe the neighbors who drop in are capable of pulling the trigger for an exclusive sale. A name tag will prove useful.

AND, I suggest taking the time to inspect those things to be sold. I can not tell you how many itmes I've found $100 bills in forgotten places like vases, books and old Bibles.

Be aware, often after the closing time a buyer will appear to take everything that remains. Have an idea what the onwer will accept for a clear out offer.

Now, if the environment is such that buyer can haggle the price, you must create a barrier to protect those who lost a loved one.  How much time is passed and who is involved are the important factors. 

Finally, what the objective? Increase the estate value or clear out the house. If the latter, there are much easier ways but those offer little benefit to you.

I would advise them to use a reputable estate sale company.  They come in and handle everything.  No need for the seller to be involved beyond saying what shouldn't go.

I always suggest that they let family and friends take what they want, donate the rest, and dumpster the things that they cannot give away.

Never worth the time spent trying to sell used stuff.

A professional estate sales company is well worth it Will!!

They handle everything.
Itemize all items,
tag with prices,
research special pricing
partner with specialists for antiques, unusual and high value items
bring display cases to protect valuables. 
advertise in advance - weekend is best, schedule both Sat and Sun

On day of sale, seller's stuff is protected, seller has peace of mind knowing prices in advances, no dealing with customers.

Total win-win.

Have them place information on all local yard sale/classifieds sites online. That helps to drive traffic. Contact a thrift store or church/charity that will pick up the rest once the sale is finished.

If it's a Saturday morning "yard sale", they need change - one dollar bills, five dollar bills, ten dollar bills.

Have a friend or family member act as a "guard".  Lots of shoplifters and opportunists show up at estate sales, yard sales, garage sales.  

Cash only.   No exceptions.

No "holding", unless you pay for it now, in cash.

Do not be insulted by extremely low offers (20 cents on the dollar) from Dealers.   Politely take it or leave it.

Lock your bathroom doors.  Tell them where the nearest grocery store or convenience store restroom is, if they ask to use your restroom.  

Anything that is "not for sale" needs to be out of sight. 

Will Hamm I agree with Ryan Huggins - Thousand Oaks, CA .  A

Excellent suggestons from Ryan Huggins - Thousand Oaks, CA and Wanda Kubat-Nerdin - Wanda Can! so far so I am not going to repeat what has already been put forth.

Masks, hand sanitizer, gloves, bottled spring water, etc. We have auction companies here that can handle estate sales. I usually call Damewood. https://www.damewoodauctioneers.com/company/our-services

What Ryan Huggins - Thousand Oaks, CA said.

I have experience with two estate sales, one for my parent's home in NM and one for my in-laws home in NY. Both were handled extremely differently with totally different results.

What I will say is that if you are going to be doing this without an official company because of long timeframes, you have some great advice from Annette Lawrence , Palm Harbor, FL 727-420-4041 and Fred Griffin Tallahassee Real Estate above. Security is very important, as is flexibility. Definitely have some flyers about the house handy, even if it's not for sale yet. And anything that's not for sale, has to be out of the house and/or hidden somewhere. 

Good luck!

Most of our estate sales condos  - relative out of Florida and they come over and deal with it. I am sure, your help will be appreciated.

That is very nice of you, Will Hamm 

Put it in FB Marketplace & Craigslist also.

Mark and price all items for sale ahead of time...Also, there is a fine line between liquidation and making money that if not kept in balance causes mayhem. Too much money the stuff stays. Less money, the stuff goes....

Cross your fingers!

The answer is easy a reputable estate company... I had one a few years ago and they sold 90 % of the stuff because they marketed it to the right platforms... and on a side note they had put out their own signs...Endre

Use a known estate sales company with a good rep in the area. They know what to do (marketing, pricing, etc.) and should, and can, handle everything. And many will take away what doesn't sell. Huge value in that. Otherwise it might be no more effective than a garage sale.

market on facbook and various related web sites

You have some great responses here, Will. 

Covid essentials, masks, hand sanitizers

Refer them to someone to handle the sales.