I've noticed that older folk tend to accept the loss of any function, capability, as 'normal', for their age.
And that it feels really odd to lose one little thing at a time. We don't realize, when we are younger, the hundreds/thousands of capabilities we have.
If, say, a pinkie finger goes numb it is surprising, then we accomodate the loss into our routine, our expectations. Or, we begin to massage and exercise it...depending on its importance to us.
We may not have heard that the loss could be caused by a critter.
Good for you for helping your dad! I'll bet he is amazed, and feeling younger!