I'm pretty sure it's only considered child endangerment if she is using infront of the children, or is under the influence while responsible for the children. I would do some serious investigating and have proof before you make any accusations.If you have not seen this happening then you really don't know what is going on. But you should, if you suspect this, call the authorities and have them check things out. If you are doing it out of spite because you don't like her having the children, then you need to leave them alone. Let your son deal with the custody issues and any problems involved.