Hi Flower-Baby,

Ironic, my Epiphyllum played a trick on me, too.

I bought the Epi at a garage sale, mid-90's.

A couple years later it bloomed.
Flowers

{{gwi:96685}}

The following years, Epi had the same color/shape blooms. Pink and white. 8-20" long.
The flower opened at night..

Then, I believe it was around 2010 when I noticed buds.
Here's what they looked like.

{{gwi:96686}}

Flowers were red, roundish in shape.

The last couple years, flowers grew in pink and white as before.

What's with that? lol

I looked at the main trunk..there's one. How on earth did the flowers change? Totally opposites.

Similar to your grandma's and moms Epi's..

Why and how does foliage/blooms change? I haven't the faintest.

Your moms and grandma's Epi's are gorgeous. So full.
I love the photo of your grandma sitting in a chair, and her humongous Epi behind.

Will you be getting a cutting? Toni

Those pics are awesome! The 1st thing that's wrong? It's not at my house. But I think you are wanting to dig a little deeper, into secondary faults...?

Without knowing what your plant is, I would ask what way was that window facing, where Gramma's plant is sitting in every pic with enough background to see location? And what else is different? Rain vs. none? Tap water vs. well? Humidity vs. very little? Gramma's plant is HUGE! Some plants take years to reach maturity. Does that apply to this plant? Of course IDK since IDK what it is.

It sounds like this plant was in the same pot for 7 years and repotted a year ago? Has it ever bloomed since its' start as a cutting?

What time of year did Gramma's plant bloom?

The answers to these questions should help others help you, I'm outta here...!

Hopeful-
That is so strange! The first one looks like a flower from a night blooming cereus and the other just looks like my picture.

Purple-
It has been re potted several times in the last 8 years, my grandmas was watered with well water and my moms with city water, my grandmas stay inside and my moms goes outside.

Humidity is about the same.
It has never bloomed for us, but my grandmas bloomed every spring and it was so beautiful! It even got little fruits/seed pods sometimes :)

I just got some awesome advice from an Epi grower who makes his business from growing and selling epis. it says to repot (not pot up) often. And fertlize. Said a semi shaded area with bright indirect light works best. He has his growing with just a partial shade cloth so they dont get burned. Theres a posibility that its not getting enough light. I'd also suggest dividing it into a few more manageable plants. You will then have the mass required to try a few different places with lighting etc... I have mine in a north east window, as well as a south west window. Just like my hoyas. they've been growing like weeds!