C.S.
My kids almost always will calm down if I take them outside. Can he take them for a walk around the block with a stroller and front pack?
My husband used to hold the baby close and do really deep knee bend bounces, almost jumping at the top, and this would almost startle them out of crying and calm them down really quickly. Also, try holding the baby on his chest and humming in a deep low voice, babies seem to like the vibration of that sometimes.