Dear Mr./Ms. Bossname,
As you know, my mother recently passed away. Thank you for your support as I attended to her end-of-life care and subsequent arrangements. I now need to let you know that I’d like to resign at your earliest convenience.
Unbeknownst to me, my mom had a sizeable estate which is now in my hands. I will be able to support myself while managing her properties and investments. I want to mitigate the impact my departure has on the team at XYZ Company, and can make myself available to work for another three weeks. I can extend that an additional month if remote work is permitted. (I will be relocating to Othertown.)
Please let me know how you would like to proceed. I will begin notifying my clients as soon as I hear back from you.
Thanks again for everything.