Help with Kids Who Refuse to do a Skill

For context, I'm 19y/o, and I own my own backyard private lesson business in its 3rd season (I have 4 years experience total). Lately I've been noticing a few kids who flat out refuse to try things, and when they do "try" I can't count their attempt because they aren't actually doing the skill (i.e. face in, but they barely touch their nose to the water)

For example, there's one swimmer I teach who flat out refuses to put their face in the water. Ears, chin, even mouth and a little bit of their nose is fine, but more than that they just absolutely refuse. They're about 9 y/o with very little swimming experience and it absolutely terrified of sinking/ drowning and equates putting their face in the water to drowning.

Similarly, another swimmer refuses to try doing glides outside the shallow end, which unfortunately isn't large enough to have them do the required distance for their level while inside.

I really try to hype them up and say how brave they are for trying, and explain its okay to be scared, that we can still do things even when scared, but I'm at a bit of a loss at this point.

Should I pull the parents into this? Any advice would be greatly appreciated!!