I would suggest next time please use following additional documents also to make your case strong:
- Property papers in your mother's name
- Sufficient funds / shares / FD's / Bonds etc along with statements for past 6 months of all these.
- NOC from school / college from where she is working and mentioning that they have granted leave to her to visit canada for XX days.
- Salary Slips
- Return Tickets
- Cover letter (that you are there to take care of her in case required and give your residence proof like electicitity bill etc. / copy of your work permit / employment proofs / salary slips / bank statements) Trick is more the merrier
- Tell her to write a letter also explaining the reason to travel and mention that 'I will return as per the iterninary attached'
- Attach vaccination certificate also
- Attach her insurance also (Indian one or take an insurance for her visit days from Manulife or any insurer)
In case of any further assistance, please DM me, we can connect over a call.
All the best. Dont worry, it will be through soon.