I don't believe it would work for this case. Typical DDoS is just sending a ton of junk packets at a server at the max bandwidth of the network of bots an attacker has at their disposal. Very easy to block for a large cloud provider with multi-terabit connections and multiple redundant data centers. This is different, they're asking the server to send them large amounts of information on repeat, or process massive amounts of data. The attacker is targeting the servers hardware itself through legitimate processes, so a third party wouldn't really be able to do much.
I don't believe it would work for this case. Typical DDoS is just sending a ton of junk packets at a server at the max bandwidth of the network of bots an attacker has at their disposal. Very easy to block for a large cloud provider with multi-terabit connections and multiple redundant data centers. This is different, they're asking the server to send them large amounts of information on repeat, or process massive amounts of data. The attacker is targeting the servers hardware itself through legitimate processes, so a third party wouldn't really be able to do much.