Residency Order For Kids

[Philta]

My son is going to court in Sept for residency of his kids. He has stated the facts which are that his wife was arrested for assault and neglect of kids and is still on bail until end of August. My son now lives in emergency housing as his landlord who is his mother in law evicted them. My son has paid for contact for kids to see their mother as it has to be supervised. His wife has tried to get him arrested saying that he broke her nose in 2012 which is a lie she fell over drunk. And also theft for taking things for the kids from the day home. She gas now put statements into the court from herself and my son's eldest son saying that he beat his eldest son and let him play with cocaine bags. It is a pack of lies will the court see that this is just a tactic to try and take kids from him. My son has had the kids for 3 months now.
I am at my wits end and not sure how to help