Interview - cancellation?? Do i?

Hello. Want some advice, i applied for a position at my current workplace have the invite for interview cone through today. Haven't yet responded. The interview is scheduled for next week however since the application hand in my anxiety has been through the roof and the date of the interviews is the exact same date time as an operation of a close family member which is ugly increasing my anxiety. I really do not have the strength emotionally to attend the interview and go throughtye whole process. I really don't. Bear in mind i am not a registered carer for this family member but do help care for then.
Getting up everyday is a chore itself. The interview is scheduled after my working hours, I'm hoping to try and attend work as normal with increased breaks perhaps that day.

Does anyone know what i can do?