Canadian moving to US for 1 year

hello, first time typer here. My wife is a dual citizen and we and our 3 kids live in Canada. Her grandfather lives in Florida and is in desperate need of help. What would we have to do to legally live/work in Florida for approx 1 year? We just started talking about it and have no clue as to where we should start.

Your children are dual citizens by birth likely, you'd just need to register their births with the US consulate nearest you. Eligibility will of course depend on how many years your wife has been away from the US I think.

While you're at the US consulate, you can also fill out the paperwork for her to sponsor you to immigrate to the US.

Here's the link to the Consulate in Toronto

And info about spousal sponsorhip http://www.amcits.com/immigration_usa_relative.asp