curly on Family Tree Circles

I am researching my mothers family lines. I am trying to trace two Forgie families one in the USA and another in Canada.
Two of my grandmother's brothers.

John Forgie emigrated to Chicago Illinois in 1921 and is in the 1930 USA CENSUS as living in the area of the Stock yards Chicago, herein is my problem I have hit the brickwall and i am having no luck tracing the family after that date.

David Forgie emigrated to Ontario Canada with his wife and daughters in 1928. I have been able to trace his burial to Chatham township Wallaceburg, but as with his brother John, it is very difficult to trace them, in fact I have not!!!!!!

Any assistance would be greatly appreciated and I would reciprocate with assistance in Northern Ireland look ups etc.

Here's hoping !!!!!!!!!