My grandmother has multiple fingertips that will not straighten all the way. She says that they do not bother her but they look stuck.  Should I take her to the doctor?  What could they do for her?

It seems you are describing mallet finger, a condition where the tendon that helps to straighten your fingertip ruptures.  Typically treatment is only sought if it becomes an aesthetic issue or interferes with your ability to do something.  In your Grandmother’s case it seems that she is not bothered by her fingers.