[duchy]

Originally Posted by meboo

Oh - I have just seen the two excellent posts that suggest a friend of mum’s could walk to your car. Now with my school mum hat on, we often helped each other out like this for eg if someone was running late.

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This was my first thought , the Mum community is usually more than helpful when it comes to stepping up at primary schools with small stuff like this that makes a huge difference.
When I was in a tough spot (Mum was felled by a brain aneurism and it was touch and go for several weeks) the Mums were brilliant . Oddly enough it was the working Mums rather than the stay at home Mums who tended to offer first, maybe because they knew what it was like to juggle more .
Finding a Mum willing to walk your grandson to the car should be very easy . Just make sure the school know about the arrangement.