this is correct. No idea what is exactly the right thing to do in terms of best for them. Consult with fiancial advisor/accountant etc.Only cash in case of exceeding CAD 10,000 has to be declared while landing.
If your parents have plans to transfer funds or assets to acquire properties here, they have good opportunity to declare during landing.
The best thing is that you consult an experienced financial advisor. It is difficult to get good advise in thread about this. @YVR123