Complex sentence: Russell P. Friedman joined at the Grief Recovery Institute in 1987, as a volunteer and eventually become a full partner, and co-author of the revised edition of "The Grief Recovery Handbook" (1998), "When Children Grieve" and "Moving On".
Split into simpler sentences: Russell P. Friedman joined at the Grief Recovery Institute in 1987 as a volunteer and eventually became a full partner. He co-authored of the revised editions of "The Grief Recovery Handbook" (1998), "When Children Grieve" and "Moving On".