Can my father's wife get all his belongings even if she was left one dollar in his will?

Yes, in Florida if a person is survived by a spouse, the spouse gets to keep the first $20,000 in household property and up to 2 cars. However, there is an exception if the item(s) was specifically bequeathed to someone else in the will.

Unless there is a anti-nuptial agreement in place, a deceased spouse can no longer disinherit a surviving spouse in Florida anymore. So the $1 possibly won't work. She would be entitled to at least 30% of his worldwide assets, with set offs of assets that may have been jointly owned between them or she received as a distribution from him. This includes assets that were jointly owned with someone else or payable to someone else (like in life insurance).