Welcome to SR ...
I'm so sorry that your family is going through this.
My situation is not exactly like yours; but my Boyfriend relapsed right before Xmas and suffered an od with time in hospital; so I can relate to your raw emotions.
There is lots of information here and your not alone with your fears.
Others will be along with more knowledge than I have; as I'm new to all this also. Came here in a panic couple months ago, but Ive learned a lot and grown stronger.
I think it's normal to experience a range of emotions right now; just give yourself some time to process all of it.
Is your husband in hosital now, or did he go into rehab?