"Command these things as well" or "Also, teach these things with authority." Timothy was to obey Paul's words himself <b>and</b> also to command others to obey Paul's words.
"so that no one can find fault with them." Possible meanings of <b>they</b>: 1) "these widows and their families" (UDB) or 2) "the church." It might be best to leave the subject as "they."
"… is worse than those who do not believe Jesus" or "those who do not believe in Jesus are better than …" Even those who do not believe in Jesus take care of their own families; how much more should believers do so!