If they require 24/7 care and they (not you) meet the requirements, it is possible. Your parents will need to meet LICO and then add the salary of a full-time caregiver. If the wage is $18 per hour then estimate $35K per year. Also, they need to post the job in Canada and prove they couldn’t hire anyone locally. They will need to set up a business registration number for payroll. Being your sister, the application will be more closely scrutinized. Then once they have complete the process, she can apply to the HCCP program