Spencer is non-verbal and only says a few words to his parents Stacey Rhodes and Craig Costello and close family, but he's now started to say "hello" and "goodbye" to Claire too.
Claire, who works on produce and has been at the store for three years, said: "Spencer has a fascination with doors and one week he was looking at the doors at the back at the store which goes into the warehouse. I let him have a go at opening and closing the doors and let him peek through and he loved it.
"Every week now he makes a beeline for me and I always make sure I'm on the shop floor at around the time he comes in so he can push the doors open. His mum says he gets really excited to see me now. He always has a big smile on is face and he looks happy.
"He's a lovely little boy and I always ask him how he's getting on at school. He said hello and goodbye to me the other week and I actually cried; I was choked.
"Hopefully, I make it a bit easier for the parents as they found shopping with Spencer a bit difficult before."
Spencer's mum Stacey, who lives in nearby Normanton, said: "Shopping at one point could be an horrendous experience.
"But we have got to a point now where we can take him and this is why it's so important for people like Claire to make it a bit easier.
"Ever since Spencer has been able to walk he's been obsessed with doors – opening and closing them. At the back of the Glasshoughton store there are doors to the warehouse and on that first day Claire noticed him as he was stood looking at them and holding his yellow rubber glove and he takes everywhere with him.
"Claire let him open and close the doors and have a look inside and it's gone on from there every week. He goes to find her and runs up as soon as he sees her. He really loves her. I think he makes her day too now!
"Over the last couple of weeks he has even communicated with her. I was so happy for her too that he'd said a few words to her. It shows that he trusts her.
"After he's seen Claire and had a go with the doors he's happy and we can continue with the shopping, whereas before we may have only managed to get so much of the way round with Spencer. Claire makes it so much easier for us all.
"I can't thank Claire enough for being so understanding; she shows that she cares. You don't always find people are like that. They have developed such a lovely relationship."
Sandra Davies, the store's customer trading manager, says everyone at the store is so proud of Claire. She's also nominated her for an Asda service superstar award.
She said: "The mum spoke to myself and said Claire was such credit to Asda. She was so impressed by the way she always asks questions about Spencer and how's he doing at school and things like the. She always shows a real interest.
"She said there should be more people like Claire in this world and she just wanted us to recognise Claire for the work she does and how happy she has made her and her little boy feel when they come shopping which can sometimes be challenging. Claire and Spencer have developed such a lovely bond."