never thought this would be my life...

please help! I have no clue what to do, if anything. My father in law is an addict, he has been supposedly clean for the past 6-8 months. Well Saturday he was at my house while I was working. My husband thought he was fine but at 2am Sunday morning he was high on meth, attacked his wife and is now in jail. I was told meth can be released through sweat glands in the user and passed to others. He was holding my son and now I'm worried. if he never was clean to begin with was my son exposed to meth this whole time???!! what do I do 😔😔 never did I think I'd be here. do I take my son to be tested? is this even true?