Where can I find a publiuc defender to represent me in family court?

You need a Washington lawyer, but I can tell you that the state only pays for representation when the sate is prosecuting you-- for a felony. That...

How can my family legally strip my grandfather of his power over important decisions made for my grandmother?

For assistance with this you need an elder care attorney and/or a probate attorney. But if you are right he is not up to the job--for whatever...

If the family law court orders me to attend Batterer Intervention Program, what is the affect on my immigration status?

You need to ask an immigration attorney. On common sense-- I;d attend!!! and I would clean up my act!!!!!

Modification

I agree with Rebecca, but I would add that I recommend that you seek some family therapy or parenting classes,and (at mediation--this WILL be...

Who gets the estate???

This question cannot be answered based on the information provided. IF the home was in joint tenancy AND the affidavit if death off joint tenant...

That depends on what the judgment says, but conflict between parents is always harmful to to the child(ren). Always, no matter how "wrong" one...