While this plan may be well intentioned, it must be abandoned immediately. If this husband and wife fail to do so, they could easily end up committing a felony. Let me explain.
Cuba and a number of other nations are declared “sanctioned countries,” including Balkans, Belarus, Burma, Ivory Coast, Democratic Republic of Congo, Iran, Iraq, Liberia, North Korea, Sudan, Syria, and Zimbabwe.
In order to transport anything into a sanctioned country, you need a license or permit issued by the Office of Foreign Assets Control (OFAC)—an agency of the US Treasury Department that administers and enforces economic and trade sanctions. The permit process can take several months. Along with that, a permit is subject to a variety of limitations. The chances of this couple, your church, or a ministry obtaining one is highly unlikely.
Don’t even consider the other alternative. Trying to “sneak” goods into a sanctioned country is a very bad and illegal idea. The couple could end up in a Cuban jail.