Ex is neglecting our son (bruises, rash, dirty clothes) Can I keep him from seeing her even tho we have 50/50?

Social services and the court system don't really care about the kids. My divorce has been in process for a year and half and my ex refuses to sign the papers. I have had an attorney but he has cost $15k and hasn't done a thing! She may have gave birth to our son, but she is not a mother. My son comes to me with bruises, sick, skin rash, dirty skin, dirty clothes, etc. He has had to get stiches while in her care because he fell off her bed, then she refused to get the stiches removed leaving them in 8 days past the doctors recommendation. She doesn't have a bed for him to sleep in, he shares a bed with her in a crowded house. She puts him in daycare for 10 hours per day while I am at home every day (I collect Social Security for a leg injury). She refuses to let him stay with me while she is at work. I've had to take him to a nutritionist because he is underweight for being a 3 1/2 yr old (weighing only 26 lbs). She feeds him fast food daily, and doesn't make sure he eats good nutrious food. When I told her that he should be having Pediasure drinks and vitamin bars daily, she accuses me of trying to make her spend more money. She uses our son to get even with me, she did drugs while she was pregnant, she has been in several car accidents, she still uses drugs daily. We have 50/50 custody but I need to do something NOW, I can't wait another 2 months before we go back to mediation and nothing ever happens. It's the same thing every 2 months. I want to go against the court order and just keep my son, but I'm afraid that will lead to greater problems. How do I expedite my case in front of the judge?? I'm in the process of getting a new lawyer, but I feel helpless and am running out of money to continue fighting this with pricy lawyers who get nothing done. Please Help a father who cares for his son!!