Yep. VISAR bases out of Tortola and Virgin Gorda, so they have close access to most places. 767 on a cellphone or a “mayday” on ch16.
https://visar.org/contactOn land I believe (make sure you check) 911 and 311 is the emergency phone number. (Police/fire/ambulance)
I know how you feel, I’m taking my 70-75 yr old parents and in-laws this year, it’s definitely something I’ve considered more this time than any other previous “friends trip”.