NBFR Who wins this argument?

dmndsr4eva

So my small dog became ill last week.  I took him to the ER vet and now to the regular vet and most likely he got posioning from rat poison or may have cancer.  He is having an ultra sound tomorrow to determine if it is cancer. 

The vet said that rat posioning can gradually cause the organs to fail and can come on slowly.  However, it has been 1.5 months or longer since he could have been exposed when we moved. 

My FI is maintaining that there is no way it is rat poisioning.  When we lived in our old house there was a mouse problem and he got poision.  I told him not to and was very upset but he did it anyways.  Now come to find out that my dog may have been poisioned and I read on the internet that 10,000 children a year are exposed to this poison.  And that the brand he used was banned by the EPA earlier this year because it is so dangerous to humans, animals, and wildlife.

I am so angry about this and thank god it wasn't my son.  He still is maintaining that he has no problem using rat posion in the future despite my wishes and that there is no chance this is his fault. 

What would you do?