See if Ribbon can help your client here: https://ribbon-buyer.paperform.co/.
Buyers in competitive situations
Offers that do not require a mortgage to close (aka "Cash Offers") are 2x more likely to be accepted (Source). Ribbon Offers are guaranteed to close because Ribbon will buy the house in case your buyer can not. Because sellers need the certainty, they love Ribbon Offers and help your buyer stand out in a competitive, multiple offer situation.
Buyers who need to sell (back-to-back closings)
In a hot market, sellers are less likely to accept offers contingent on a home sale. With a Ribbon Offer, your client can make a winning offer on their next home, then you and your client can take their time to sell their current home without sacrificing price.
If your client has not sold their previous home before the closing date on the new home, Ribbon will purchase the home first and reserve it for them. They can move in and rent immediately and potentially fix up their previous home to sell it at the best price possible.
This removes the stress and timing issues of a back-to-back closing. It also helps you win new clients who are too afraid to move because of the timing issues and stress of having to find their next home and sell their current home with perfect timing.