1. A person can change his signature at any point of time and mere change of signature does not cause harm in title of property.
2. Even with the passing of age the signature of a person changes and it also does not adversely affect the material management of the property.
3. So you can relax at least on this account.
4. However where disbursal of money is done only after putting signature there updation of her present signature is required to be done.