I have a question about the DCFS?

My girlfriend has two kids, one is 4, and the other is 5. The 4 year old is fine, the 5 year old is severely troubled. He's got severe abandonment issues, he's been diagnosed with ODD, Oppositional something rather. Onset Pediatric Bi-Polar, ADHD, and they're looking into Asbergers. Well needless to say, he's a handful, He's manipulative and violent. I was raised with a black leather belt, and I know that's illegal nowadays. I've used a belt a few times, as a visual for him, to get him to stop doing whatever it is he's doing at the time. I know that soap is out of the question, as it could be Noxious. I have used Franks RedHot Original many times when he's dropped the F bomb, along with some other choice words. Note that Franks is the mildest hotsauce out there, with Tabasco being nearly twice as hot. I've always put a drop on my finger and rubbed it on his tongue, but always have given him milk to subside the burning afterwards. I had just talked to DCFS, a report has been filed against me, for Poisonous/Noxious Substance, and Possible Physical Injury/Injurious Enviroment at home. I told the social worker, who was very understanding, everything that I've done. She admired my honesty to the fullest extent, and doesn't think that anything is going to come of this, but is required to "investigate". He's been kicked out of school twice already, within 2 weeks, mind you he's 5 years old. They are looking into something like, SAS program? Counseling, and alternative schooling. We've got a very safe enviroment at home. Neither of us smoke or drink, we don't have any firearms or ammunition in our household. Our chemicals and kept up high, our stove knobs are removed and kept away. We have a brand new and working, Carbon Monoxide alarm and Smoke alarm. Knives and other pointed utensils are kept away, They both have beds, tons of toys, tons of clothes and abundance of food at their disposal. He's taking .5mg Risperdal(2x) 20mg Adderal XR(1x) 5mg Adderal(1x) 4mg Singulair(1x), He's obsessed with morbid and gory topics, movies, games etc etc. He has frequent Nightmares, and wakes up screaming, hallucenating. Say his brother pulls on his arm, he'll tattle to us that he broke his arm, or if he falls and hits his head, he'll say he's going to bleed to death. He likes to take things to the extreme, and a report was filed against me yesterday that I dump hot sauce down his mouth and smack him with a belt. I have always put a drop of it on my finger, and I have never touched him with a belt, just snapped it to get his attention. I'm just telling you what I'm dealing with, and in hopes to get some advice about what could happen. Oh and her last boyfriend got DCFS called against him saying he rubbed his nose in feces, it was unfounded but I see a pattern starting to form, don't you?