COVID 19 jab

I understand as my mother thought doctors were God and she had them on a pedestal !  I think my generation is far more likely to query things.  Most GPs seem to pass patients on to specialists very quickly these days.
If your Mum is on a pension she is covered for the ambulance, for one trip anyway.
Do you have a blood pressure monitor or even a Fitbit which you can pop on her ?
Perhaps stay with her on the first night 'just in case' ?  Try not to worry her, though.