@AdamKoebel Why are the characters required to make a CON save to enter a long rest. This is just a normal jail cell with no beds. - I get it, dirt floor and all. But its not like they are sleeping on a bed of hot coals or anything out of the ordinary for a poor quality prison.
Given Berg’s level of exhaustion it should actually be easier for him to get to sleep. If you’ve ever stayed up for beyond 24 hours and the stimulants have all worn off then it is quite easy to fall asleep regardless of the comfort of the bed.
No where in the rules does it state comfort is required. Nor does it state how much actual sleep is required. Just that they cannot take part in “Adventuring” activities.
Of course your the DM, but if I were at the table I would lawyer this quite heavily.