@Arafat ,
This is an improper word choice.
"He wants to be a moderator in their divorce. "
or
"He wants to be a moderator in their divorce proceedings. "
The use of toward is often used when something physical approaches or has adjacency or closeness.
When it's used in reference to an abstract subject or object or a non-physical one...it indicates something is getting closer to the subject or object either in time or proximity.
As an example:
"The court case is moving toward conclusion."