so sorry to read this. Cave diving is particularly dangerous. A VERY advanced form of diving. My nephew is a dive leader in Puerto Rico and when he visited me in SD he went out with this team
http://cavediving.com.do/website/ which teaches very advanced diving techniques.
I worked with a diving operation in Haiti back in the late 70's - it attracted some of the most adventurous divers in the world (since the nearest hyperbaric chamber was in Cuba - do not know if the DR has one - but that was a long time ago and diving has come a long way - lots more people doing it - and lots more instruction - the odds of anyone getting "bent", getting "the bends" which can happen both on a deep dive and on a long dive -are much less now since everyone has the decompression tables attached to their equipment)
The DR probably has lots of dive sites that have not really even been "discovered" - it is not promoted as dive destination - which it probably could be. I met a group of divers down in Pedernales - Dominican divers from the Capital- who were taking a boat from there out to Isla Beata -- and wanted the "fisherman to stop fishing" because they were taking the fish from the reef.
It was always sad for me to see some of the gorgeous reef fish being sold for eating.
https://divezone.net/diving/dominican-republic
RIP