Thomas is called to be a missionary!  HE is promised his family will be watched over and provided for.  He has just joined the church and leaves 3 boys, the oldest of whom is 9.  Much like Joseph Smith, he has to put his trust in God's caring for his family and go and do God's work.  Love that HE is called a physician.  Much as the Savior was called.  He was sent to heal those who needed healing through the gospel word.