How can someone in Thailand with a tourist visa and dengue fever get a visa extension or exemption?

Hi, my friend was due to leave Thailand (visa expiring) on Thursday, and she’s just come down with dengue fever. She’s in hospital. We’re on an island and she can’t get to an immigration office, let alone the border. Anyone have experience getting an extension or exemption under such a circumstance? Over the phone? She wants to be able to return in future so doesn’t want a red stamp, but she’s way too sick to travel now (or even use her phone, so I’m posting for her!) Advice appreciated. (She’s on a tourist visa, already extended. Nearest imm office is Samui (different island) in case that makes a difference...)