Could this magic item help Ezmerelda in Curse of Strahd?

In the Curse of Strand adventure, the following information is provided about the NPC Ezmerelda in Appendix D (p. 231):

There’s also this magic item that can be found in the village of Krezk (p. 148):

The sunray lasts for 1 minute. If the characters smash the gravestone without placing Tasha Petrovna’s holy symbol in it first, they find nothing within its remains. The ring is a ring of regeneration.

The description of this magic item in the DMG says (p. 191):

So the question is: