Also obvious- you aren't holding him/rocking him to sleep at home, putting extra blankets in the crib, he is sleeping in a crib/no swing or car seat, no bottles in there, etc?
There are state licensing requirements, and I find that if parents are doing ONE thing different, that's of course the one thing that the child 'needs'. I don't take infants anymore, but when I did I had a similar issue. Mom came in to show me how she got him down for nap. Dark room, rocking for 20-30 minutes, and then she handed him a bottle and put a blanket on him.
NONE of which I could do.
I also won't term unless the parents aren't working with me- unless a child is violent.