Thank you for writing in,
There are several ways to achieve this, but I always want to caution people who want to take on Medium abilities that you be absolutely sure you want to talk to the person. When it comes to family members I suggest a long reflection on the fact that you may be provided information by the spirit of your relative that you did not want to know. Spirits are often not the ideal of modesty and you should be prepared to hear things & learn things you did not intend.
If you desire to communicate with the deceased (and it does not matter how they died) you can utilize enchantments or spirits to aid you in this.
You can work with spells that bring the owner Medium abilities, you can work with enchantments that carry messages between the Earthen & Spiritual Realm, you can task spirits to relay messages for you and bring the response.