I just checked on Expedia. It shows round trip for around $1100. His wife is an American citizen, she has lived here for several years, and he may have purchased a one-way ticket. So, he could possibly have flown here for around $600.
He flew in from Liberia in Africa, not Liberia Costa Rica. Check Expedia again.
Brussels Airlines and Royal Air Maroc are the only airlines still flying out of Liberia because of the Ebola outbreak and they are not on Expedia.