Tell your husband that his friends are living in the stone age Just because it has "always" been done that way doesn't mean it is the BEST way! Have them come over and see how your chicks do NOT act like the chicks they raised under a heat lamp. They will likely be worried because the birds are quiet and SLEEP at night!
Ignore the thermometer, watch the chicks. If they never go in (after you show them the cave!) it is too hot. If they never come out it is too cold. If they come and go it is JUST RIGHT. Lower the temp based on that behavior as they get older.
I used paper towels over newspaper the first time (heat lamp in the bathroom
This was back in the stone age of 2012) for a couple of days then gave them shavings over newspaper. The 2015 chicks went out to a brooder in the coop with a broody hen at 3 days old. Nothing but shavings in there. Never had a problem with the chicks eating shavings either time.