The Bees secured Eriksen on a six-month deal in January as he sought to return to football after a cardiac arrest at last summer's Euros.
The midfielder has been outstanding in a Brentford shirt and Frank says: "As I see it from our side, I think it is a win-win.
"He has given something to the team and he has given the fans something that they had never seen before in terms of level.
"We helped him get back to football life again. If Christian decides to stay, our fans will build a statue of him in three years. If he chooses to take the step further to another level, we will still welcome him."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!