I feel there is a conflict between ‘has’ and ‘told’. Accepting that the subject is still living and still has a poor memory, it is not clear why the tense changes to ‘told’. By using the past form ‘told’ we are going back to the time when she ‘told’ the stories and at that time she ‘had’ a poor memory. Grammatically it is of little significance that she still has a poor memory. The two verbs ‘had’ and ‘told’ are linked and need to be in the same time field.
Without any context, it cannot be simply assumed that the old woman is dead OR that she is still alive (and still has a bad memory). If this was a test question (i.e. without any other context), it would be “safest” to use had since the sentence talks about something that happened in the past.
However, if context confirms or suggests that the old woman is still alive today, it certainly wouldn’t be wrong to use has.
Oops, I see Alan has answered already and I agree with him. Please keep in mind that my comment about the present tense being OK would be dependent on additional context (which you didn’t provide).