Can my son live our house if we have guns and he has a felony conviction for child neglect?

The question depends on whether he can be treated as having constructive possession. Violation of his probation takes a very low standard of proof. It isn't that you can not own firearms. It's that it may be less than a stellar idea for him to rely on my parent never told me the code, particularly if there is an automatic record of each entry into the closet.