I get the "You're such a guy" often from my wife. Usually over things like not scubbig out the kitchen sink and how I don't poses that female "seeing dirt at at an atomic partical level" gene. At least I got my mom's hips

At my age I cannot imagine emailing, forget texting, my wife about something this important. Since I work out of state the really important stuff waits untill I head back home so we can talk in person. We may spend an hour or more most nights on the phone but some things just need to be said face to face.
However, I am also guilty(?) of writing my dad a letter over an important family matter. So I can fully understand the reluctance. BTW I was also never expecting to see or much less have any contact with him again.
IMHO, I would recommend first telling your mom. Then play it by ear. Drop the "T-Bomb" and let the questions come. It is going to be overwhelming for her. There is no way this stuff is going to sink induring one conversaion. It took you years to sort it all out and you were living it. Can you expect more from a bystander?