Quoting: leafs101
I'm pretty sure he can be offer sheeted when his contract is up. If he took that cheap of a deal it would be on a 2 year deal
Because he played games during the 2018-19 season after signing with the Canucks, his expiry status became RFA 10.2(c). If you look this up in the NHL CBA FAQ portion of the Capfriendly site, you will see that this definition comes up for the type of status:
"The player is only eligible to negotiate and sign a contract with the club that holds their signing rights. They are ineligible to negotiate a contract (offer sheet) with any other club. They are also ineligible for arbitration." -
https://www.capfriendly.com/faq (What is a 10.2(c) player?)
This means that although he will make a lot of money on his next contract, the Canucks have much more leverage than he does.