I filed for a Request for Order for my four year old son's joint custody.

Hope your court date is soon so that you can get to the bottom of this as your child is clearly hurting due to the conflict/ parent's behavior.

You must be entering into a stipulated judgment. If he does not sign the form you can have his petition/response stricken and take his default.

What can I do if I can not afford a lawyer for a child custody case?

Various counties have legal aid and other low cost options for legal counsel.

How can I enforce terms of my divorce decree from California when it was filed in Utah.

I concur with my colleagues. If it was for support, you could get assistance here.

Typically 1/2 the length of the marriage. Glad to hear you are seeking counsel to obtain answers and prepare accordingly.

My sister passed away and my family is concerned about her cause of death

I concur with my colleague. Report your suspicions to the authorities.

What is considered child abandonment in the state of California?

I concur with my colleague. Not it is time to find a lawyer.

If my ex parte request for custody was denied can I file another ex parte request for visitation?

No. You could have plead for an order shortening time. Now you are relegated to have your matter heard on the regular court calendar.

Is it possible to use emails and texts in custody case?

Yes, text messages and emails can be used as evidence.

Isn't there an age at which the child can decide?

14 is the "shall" age while children younger the court may take their preference into consideration.