No, a student "grant" is not social assistance. HOWEVER,based on what you have written, your situation is not just "fine" as is. In order to be eligible to sponsor your parents, you must meet the LICO (low income cut-off) which is currently $33,933 for 3 people (you + your parents). And based on your previous postings, looks like you need to meet the LICO for 8 or even 9 people ($64,674 for 8 and $70,621 for 9) How will you meet this while going to school, especially considering that you have a student loan??
You don't just have to meet the LICO when you apply. You need to meet the LICO when you apply AND throughout the duration of your sponsorship application. CIC may re-assess your financial situation at any point during the application process to check if you continue to meet LICO. If you don't meet the LICO, then your application will be refused.