D.A.
If the truck does not have air bags in the front seat, you could just put the car seat in the front and have the mom ride in back...it is an option if it is the only car they have. We had a full size pick-up for a while and it is perfectly legal to have a carseat in the front if it is the only place one will fit and there is no airbag, or it can be turned off.
The baby has to be in a rear facing carseat for the first year. If this is not an option, I would tell them to start looking for a new car.
D.