A good friend of mine, who is the assistant manager at store that shall remain nameless, got sick on a Saturday recently (busy day for them). She's a good manager and a good person, but she's new and so most of the employees don't respond if she texts them asking if they can cover on a given day. Despite this, she was able to find cover (including someone with a spare key to open the store) and she has the sick days available to take some leave finally (even though her company obscures how many sick days you have left, which I personally find disgusting).
However, the store got very busy and she got a call from one of the workers saying sales were falling behind because there was stock on the floor. The store is chronically understaffed (including no real manager as the old one quit and my friend had to pick up the slack, even though she'd been assistant manager for barely 6 months).
My friend has been under the hammer for 2 months and getting more and more run down and this sick day came at my urging, but when she got that call, she broke down crying and went in to work despite being sick.
I'm sort of looking for advice for her situation. She is the full-time assistant manager at a store which has no manager, so she's been forced to assume the manager duties with no increase in pay or additional consideration by her regional manager. I've checked the job ads and the regional manager has put in zero effort hiring a new manager for her store, and is making a ton of empty promises to train a new manager or move my friend to a different store (at least, I feel they are empty promises as it seems like the regional manager just hasn't done anything about the problem).
I know this sub is against managerial staff in general, but my friend is getting screwed by her company and I figure that resonates just as well. What, professionally speaking, can she do if she feels like she can never call off sick because the store is understaffed?
I can try to provide any additional context needed in comments