my father is being sent to immigration in the us as he was sent there without passport. how long can they hold him before he can get back to canada

The length of time that someone who is picked up and detained by Immigration depends upon ICE's view of the individual, Sometimes people can be released by the agency on their own recognizance or on bail with a notice to appear at the immigration court. Otherwise they are generally held until they either have a bond hearing before the immigration court, or failing that, appear before the immigration judge for a master calendar hearing at which time they can ask for voluntary departure to leave the country or for any other relief to which they believe that they are entitled.  The actual time varies dependent many times on the speed of the local immigration court.  Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.