feather duster out of tube

for a few weeks my dusters tube has been fraying, and today, he seemed to be leaning out of his tube and now he is out on the sand,.. but his crown is still open, and seems to be alive but not as reactive,..is he dead or dieing?

i don't think they are supposed to leave their tube,.. did he leave or fall out?

also added juvie dalmation mollie a few days ago,.. but have not seen them around him as i was worried they might pick at him but i haven't seen anything,..

is there any hope?

he didn.t loose his crown he's all the way out,.. but don't matter now, as the vibex snaill ate him overnight just the parital worm left.