You don't have to switch to canned if you don't want to. You can pre-soak the kibble for each meal ahead of time so it's good & soft. The advantage of this is then you don't have the potential problems caused by changing diets while trying to recover from surgery.
What I did was at each mealtime, I'd prepare a spare bowl for the following meal by putting in the regular amount of kibble, and adding warm water and/or chicken broth until the kibble is covered. Then let it soak in the refrigerator for at least a few hours before feeding so it's nice and "gummable." Then right before feeding, I'd add a little more warm water and stir, just to take the chill out and make it a little soupy. : My poor toothless Chancy got by this way for a good long time with no problem. She also enjoyed soft treats like bologna, hotdog bits, soft bread bits, cheese, things like that.
The first couple of days will be hard. He'll probably drool oozy blood for a day or two, and leave the water dish a festive red. If he's reticent about eating at first, you can try offering meat babyfood, just to get his appetite going.
Good luck.