What Do Sores On Head, Weight Loss And Fear Of Being Alone After Weaning Off Drugs Suggest?

Hi my brother is a drug addict has started meth programme ! Clean 6 weeks but not the same person doesn't come out unless partner with him ! Has sores on his head loosing weight rapid just cannot function stays in bed all day every day ! I'm starting to wonder is this hiv ??? ! As I read up and lots of symptons are the same ! He said he smoked herion took benzos cocaine and pretty much anything I am worried he may have injected and Prob can't remember