Visa officers will assess your parent's and in-laws capacity based on their ties to their home country, purpose of visit and their assets(they have the means/money to travel) to decide whether they can be given a visa.
Visa officers will assess your parent's and in-laws capacity based on their ties to their home country, purpose of visit and their assets(they have the means/money to travel) to decide whether they can be given a visa.
In my opinions:
It could be anything legal & officially represented or certified by documents that could satisfy those concerns of immigration officers.
1. Ties to their home country.
Anything proves that if they choose to stay in Canada they will be lost more than got benefit compare with go back and stay in their country.
2. Purpose of visit:
If they come to Canada under your invitation: A Letter of invitation written by you, a travel itinerary if you intend to take them to travel around Canada
Round trip flight booking, Confirmation of accommodation, travel insurance.
3. Their assets
Could be certificates of ownership of the house, land, farm, car, stocks, bonds, shareholders,...under their name or their spouse name.
4. Money
Bank Saving account book (at least 3 months period), the expired day should be after the duration they intended to stay in Canada.
Bank statement for 3 months recently.
Pension book
Or if you have a high salary you could sponsor them by submitting yours (if you guaranteed to pay for them)