in this case....the towline is already attached in the form of a dangling anchor
Use a boat hook or grapple to catch that line so as to get a bight around it then slowly pull forward to reeve up the ground tackle to just before the line turns to chain.
Tie off the chain to your stern , so that it dangles safely and slowly pull the boat towards your stern with the anchor line while keeping the boat oriented into any swell, until close enough to safely transfer a person over your stern and across the pulpit.
If too lively, put a tender
in the water
with a long tow line and drape the tender
across the drifting boat to make a transfer
Person on drifting boat should be prepared to stay onboard to keep rudder
active, protect bridal from chaffed.... if you decide to tow.
But if possible, better to get the drifting boat moving under its own power to get it into a safe haven.
This is when you feel good about teaching your partner on how to sail your own boat by herself, while you sort out the drifting boat