Should client family get this caregiver's Doctor's work permission?

Your question is very confusing but I think what you're trying to say is you're concerned about the other caregiver not being strong and healthy enough to handle the duties required to be a caregiver for your client. A migraine doesn't necessarily hinder their strength or mental status. My husband gets migraines every once in a while so I am familiar with this. I would think it would be asking too much for a work release for a migraine. The agency she works for may require it, but the family or another caregiver shouldn't. If there are other reasons you feel this caregiver isn't suitable for the 90 year old, I suggest you relay them to her family who may want to relay them to the agency she works for. Good luck!!