I really, really, really hate this part...............
The last I heard was, you stand off, circling the boat ensuring everyone is wearing their PFD, call the USCG and ask what to do next. If the boat is sinking, put everyone in THEIR RIB or life raft, transferring them to your boat IF necessary, keeping the USCG informed of your location, intentions and progress. This crap about getting close enough to step aboard your boat is asking for trouble. "Slip and Fall" etc.
The USCG may want to come out or have the owner call TowBoat.
IF you elect to tow them, if they accept your line, you are in the salvage business. If you accept their line, I think, that may increase your liability for the safety of their boat and crew.
There are so many rules to follow to reduce your liability.
IF they dont have enough PFD, toss them one or two of your own, keeping in mind you must retain enough PFD to satisfy your own needs. Dont expect to get your PFD back. SHRUG
Gone are the days of 'hand shake contracts' and helping out a unknown fellow boater, without fear.
If course if your bestest buddy needs a tow, let's hope he is not out to get you.
Sad to say but, the good ole days are long since gone.
Standing off and circling the boat, rendering reasonable aid, PFD, while waiting for help from TowBoat or USCG is indeed the safest thing to do.