>She said the baby did have white spots in her mouth, but they went away.
>She seems hesitant to go to the doctor/nurse and just ask.  I tried to
>impress upon her that thrush could keep "going away" and returning.

Here's a homeopathic method I used successfully:

For baby, mix 1 tsp baking soda (bicarbonate of soda) with 1/2 cup water.
Wipe baby's mouth with solution. You can also wipe the mouth with plain yogurt.

For mom, mix 1 Tbsp vinegar with 1 cup water. Wash nipples with solution
after each feeding.

It's too bad she feels awkward about nursing her 13 month old. Be sure to
pass on my encouragement!
--Kelly