These are the docs that you will need:
http://www.cic.gc.ca/english/information/applications/student.asp
You can get the document checklist and the required forms for your country here^
Requirements of embassy for study permit....
1. Canada application form( 4 forms available on CIC website)
2. Statement of purpose (SOP, write 2-3 pages)
3. Acceptance letter from university
4. Offer letter from university
5. Evidence of fee paid to university
6. IELTS photocopy ( must be notarized from notary public)
7. All educational documents photocopy (attested from hec, ibcc, and notarized from notary public: For Pakistani applicants only )Note: This is for paper based application since they wont return your original certificates, you can upload original certificates if you are applying online.
8. Bank statement( original documents of bank which shows your details of account and it must be six months old account. It can also work with 4 months if you pay the tuition fee for the first semester/year upfront)
9. Source of income( How much do you and/or your sponsor earns; you would have to show payslips and bank statements to show that. You also need to show property of 2-3 crore or above. It would be better to do you)
10. Family registration certificate (FRC from nadra) original
11. Police clearance certificate original
12. Polio certificate original
13. Your NIC and your parents NIC's photocopy and must be notarized. You would have to provide the same for your sponsors. If you can get a death certificate then that will be better for you as they would need proof about your fathers death. My mother passed away in 2012 and i didn't provide one and it worked for me but i think it was because normally fathers are the primary sponsors so they didn't bother much.
14. Your original passport and all pages of it photocopy
You need to show a minimum of: tuition fee for the first year plus 12000 CAD as proof of funds but the more the better. It would be highly recommended to pay the tuition fee for the first semester/year upfront as it would make your case pretty strong. Make sure the University has a 100% refund policy in case of a refusal.
Make sure to state your purpose and future plans in your SOP like what will you do with your education back here in Pakistan and also makes sure to show ties with your home country (properties, investments, ties with family members etc) that will compel you to leave Canada at the end of your stay. These two are the common reasons of refusal so you have to work on these. You would also need to explain why your relatives are sponsoring you.
Firstly, i am sorry for your loss. As far as your case is concerned, the application gets stronger if your parents are sponsoring you and they also become a family tie that will compell you to return but there is nothing that we can do here so InshAllah this will work out for you. Explain that he was shot but do not bring religion into it. If he was killed as a result of his sect, only then just mention that in a line but do not go any further. We should avoid those topics. In order to make your case strong, try to pay as much tuition fee as you can in advance as the Visa Officer will consider a situation where the relatives refuse to sponsor you anymore so it is better to show them as much money in Canada as possible. So if try to do this. Do check the refund policy of the University first though.
InshAllah it will work out for you. Best of luck!