I applied on December 20th and my review started at 09th march ,also i know couple of friends who are on review stage ,to my research i have seen trends of getting ppr after review approximately 22~28 days so lets hope for the best this coming week
I dont know if this can help you but ircc has introduced a status tracker on trv's ,hope you could track your dads and moms application ,another option order GCMS or raise a webform