I hate my parents in law and husband

Wah I feel for you. It’s not right for your husband to blame you for it. Ask him to show you how useful he is as a father before he judge you as a useless mother! Tell him you will find work to support the family instead and he stay home take care of the kid, do a role reversal if he thinks you’re not taking care of your son well enough. 😤 But seriously…have a serious conversation with your husband on options to move out away temporarily from in laws if they still cannot practice good hygiene. If you can get your son’s PD to say in his face (or you record down and replay for him) that PIL is most likely the reason he contracted the cough due to living within close quarters and poor hygiene. Then you have support from medical perspective to notify him of this.