got a call - first respite

Got a call for respite for a boy age 3. We will have him for a week or two. Hubby hasn't been so sure about doing respite but I think it helps with the wait. Not to mention it helps the other fps out as well as our agency and the sweet kids. So...he will join us today or tomorrow! This is our first respite and first 3 year old fc. Any suggestions to help him be less scared? He is very attached to FM.FM is in tears and doesn't want to do this but it is a cps forced respite for a safety plan for this little guy. (Issue with other child in home). Any great ideas are welcomed!