Overview

• French authorities have deployed helicopters and dogs in the search for Tom Doherty, missing since Tuesday.
• The retired doctor sent a WhatsApp message to his family saying he had fallen and couldn't move.
• Doherty's tent and car have been found, but foggy conditions are making the search difficult.
• His family, including his wife and daughter, have joined the search efforts in France.
• Doherty, a respected consultant in tropical medicine, has been living in France since retiring a decade ago.