I found this at www.carseat.org:
Can I put my child in the front seat of a pickup truck?
Many pickup trucks have back seats that are too small for child safety seats. Researchers at the Children’s Hospital of Philadelphia have found that the risk of injury to children riding in the back seat of a compact extended-cab pickup truck is five times higher than when riding in any other vehicle. Injuries appear to be caused by hitting the inside of the pickup.
If you have a larger pickup with a back seat that faces the front of the truck, a safety seat may be installed there if the truck’s manual recommends it and at least 80% of the safety seat’s base sits on the truck seat cushion. You can reduce the risk of injury for forward-facing children by tethering the safety seat. Using a top tether can greatly reduce the chance of a child’s head striking the interior of the pickup.
Installation of a safety seat on a side-facing jump seat is not allowed by any child restraint manufacturer.
If you must install a safety seat in the front seat of a pickup truck, disable the air bag by using the air bag on-off switch. If an on-off switch is not available, you may ask NHTSA to let you have one installed. Until a switch can be installed, do not transport a rear-facing child in the front seat. Some passenger air bags will expand to cover the center seating position, so installing a safety seat in that location may be dangerous to your child. Check the vehicle owner’s manual to find out where child safety seats may be installed. Installing a safety seat in the front seat of any vehicle increases the risk of death to your child by more than 30%, so a pickup truck without a back seat is not the safest choice for transporting a child.
And a quote from DrSpock.com...."Rear seats are safer, in general, than front seats because they are further away from the force of the crash. But an infant or child can be reasonably safe in the front seat, when properly restrained and if there isn't a working air bag."
I would check the owners manual of his truck and see where it recommends child seats be installed. My husband has a truck with a full size back seat and that is where our daughters car seat is installed. The seat base fits completely on the back seat. I would only put her in the front if her car seat did not fully rest on the back seat. Just my opinion, but I agree with you (provided it is a full size back seat). Google "child car seat and trucks" for more references if you need it.