The article "How to handle a parent not having a will" from New Jersey 101.5 says that some people may postpone this for as long as possible to avoid dealing with fears relating to their own passing. They also may feel overwhelmed by the process.
If Dad has recently passed away, Mom may be hearing, "You're gonna die soon, so please leave me an appropriate share." That can be difficult, too. Talking of drafting a Will with Mom may bring back painful emotions linked to the father's death. These feelings are natural.
It's important not to pressure Mom but instead point out some of the benefits a Will can provide, such as how a Will allows her to specify how her assets will be transferred at her death. This can include making bequests of family heirlooms to specific people or include charitable contributions. If there's no Will, Mom won't have any control. Her assets will pass according to the intestate laws of the state.
Probating an estate without a Will can mean more time and money than an estate with a Will. In addition, not having a Will leaves the heirs to contend with it on top of their grieving.
Proper planning allows Mom to minimize estate taxes, inheritance taxes, and even some income taxes depending on her circumstances. This allows more wealth to pass to her heirs.
Parents can be quite uncomfortable talking about these issues with their children, so you might solicit the help of a close friend or other family members like an aunt or uncle to help bring up the subject. Many families find that an estate planning attorney can help facilitate the process. Be prepared for this to take some time. It may take several discussions to get things rolling.
Reference: New Jersey 101.5 (April 7, 2016) "How to handle a parent not having a will"