How can I stop a child process of a subshell (as per SIGSTOP) before the subshell exits?

In bash, when running ( sleep 123 &), the sleep 123 process will continue running, when the subshell exits. How can I stop the sleep 123 process before its parent subshell exits? I'm trying to see if the sleep 123 process will be terminated, because of receiving SIGHUP and SIGCONT. I am looking for an example for https://unix.stackexchange.com/questions/484344/is-sighup-sent-to-this-orphaned-process-and-why-doesnt-it-terminate and https://unix.stackexchange.com/questions/490494/does-sending-sighup-to-a-process-group-that-becomes-orphaned-and-contains-a-stop