As already mentioned you will have to show significant amount of funds in addition to proof that you are not exhausting your own savings. It is typically much harder for a second family member to get a permit because their ties are weakened by the other sibling moving to Canada. It also appears as though your nephew has not even started school yet and had to defer his studies until January and also wants to bring his 3 children and potentially a spouse to Canada which will require significantly more savings. There will be concern that a whole extended family is trying to relocate to Canada. They are also applying very close together which will also raise concerns about your ability to support all these people and that extended family is trying to relocate within a short period of time. Does your niece also have a family that she wants to attempt to come to Canada? For her best chances of suggest she should look at advanced degrees (master and PhDs would be preferable) from good public universities to alleviate concerns about being a genuine student: Given that your nephew couldn’t work for many months after he lost his spot in the fall semester hopefully he returned home so he can support his family and not raise any concern that he is working illegally in Canada.
