I have a complex question regarding my grandchildren and trying to get custody of them.?

we live in iowa. my son's wife moved to minnesota when his kids were babies. the divorce was final. visitation involved meeting halfway. she moved from minn. to calif. doing this she broke the court order regarding visitation. right? after living in california for 5 months the welfare office came in and took my granddaughter into custody. she is 3. my grandson is in the hospital due to the stupidity of *&%$&* who let him get into a bottle of sleeping pills. he almost died. was in a coma and having seizures. a miracle brought him back! the welfare let my granddaughter be released to my ex-daughter-in-law's boyfriend's parents. there is going to be a hearing this month to try to terminate both the rights of my SON and his ex-wife. petition states that ex-wife used pot, manic depression...... nothing good.... and it states that my son is violent because of the fights him and his ex-wife had in the past. they have not been together for over 2 years. so what do we do?