Word families are very popular when teaching children to read. It's important to understand that these are generally individual sounds that are blended together into the blends that we recognise such as /ad/ which is really just /a/ and /d/.
Nonetheless, children love to group these together as they have consistent endings that sound the same or rhyme. Let your child repeat them and enjoy the rhyming features of these words.
It;s very important to get your child to sound out the individual letter sounds and then blend them together. /c/ /a/ /t/ /cat/!