Review the 5 videos in the museum, and Mews will appear to give you further instructions.
You have to look at the 5 videos in the museum and then Mews will show up. (You only have to open each one, not look at the whole thing.)
He should appear in the museum or the lab (to the left) after you have watched all of the videos in the museum.
When your surfing kite is sabotaged, Mews rescues you and takes you to his mansion. After you see him, go downstairs and to his Museum. You will have to review the videos on the 5 cryptids, and then he will appear again to offer the use of his helicopter and lab.
He appears only after you have watched all of the videos in the room (you don't have to watch them all the way through).
When you come downstairs in the mansion, go to the right and enter the museum. You are supposed to watch all five cryptids videos (or just open and close them), and then he'll come in to give you some instructions.
Mr. Mews is in his mansion, in the museum to the right. In order to lure him, you must watch his videos on cryptids. He will let you use his helicopter to find evidence.
When you are first recuperating in the mansion, you will talk to Mews, who then goes downstairs. Drink your water and follow him down, going to the right and to the Museum and Lab door. Once in the museum, examine the 5 videos that you can view. (You actually only have to start and then stop them.) When you finish, Mews will appear and offer the use of his Lab and his helicopter. From then on, he will be waiting for you at the Lab.
You find him in the lab, where you first talked to him. From the helipad. it is just to the left.
You don't. After you get the lantern and take a photo of the footprint above the monastery, bring it to Mr. Mews. He'll tell you it was a snowshoe and it's not worth revisiting. When you have proven the existence of the other three Cryptids (Nessie, Chupacabra, and the Jersey Devil), Mews will send you in pursuit of Bigfoot in the Pacific Northwest.
When you wake up from the rescue drink the glass of water and go downstairs. The butler will tell you to go into the museum. Go into the museum and there will be a sign that says Lab Room <- Museum -> go to the museum. Watch every single video about all the cryptids, the Jersy Devil, The Lochness Monster, The Giant Squid, Bigfoot\Yeti and the Chupacabra. Then Mr. Mews will appear.
When you are first recuperating in the mansion, you will talk to Mews, who then goes downstairs. Drink your water and follow him down, going right to the Museum and Lab door. Once there, familiarize yourself with the quest by watching all 5 videos in the museum. When you are done, Mews will appear again. From then on, you will see him at the Lab when you return with clues or proof.
You need him to rescue you from Grimlock.