I've done this, but I am the DH. I don't stay in the car, I get involved and let my opinion ring out on pattern selection and fabric. I even test out sewing machines before the wife buys them and have service manuals for when that is needed.
Take that DH with you, you might just find a great partner in another one of life's enjoyable adventures. If he is new at this, it's just like taking a kid fishing. Make the trip short, make it a positive thing, and go out for lunch or dinner together after and enoy the time together. He might just think: " that wasn't as bad as I thought it would be and I actually had fun".
Good luck on having fun together.