Does your dad like to experiment with food and tech? The Anova Precision Cooker makes sous vide cooking more accessible, making it a fun and easy way to try a new technique. Plus it integrates with Amazon's Alexa and Google's Assistant.
If your dad prefers the more tried-and-true methods of cooking, the Black+Decker WiFi-Enabled Slow Cooker is a cool kitchen gadget that adds smarts to a cooking interface almost every parent is familiar with.
If your dad is getting into more healthy foods, the Vitamix Ascent might be a good choice. This Vitamix knows which container you're using, and automatically adjusts the settings to get the best blend -- perfect for protein shakes in the morning.
If your dad doesn't spend much time in the kitchen, a digital assistant might be a better option. The Amazon Tap is a smart speaker that docks to charge, but can be brought around the house for Alexa access or music.
If your dad likes to carefully control his home's temperature, try sending him a Nest Learning Thermostat. Then, every time Mom changes the temp, he can switch it back from his phone, without even getting off the couch.