Dates, Strings and Nonsense

Question

I had some disturbing mail through the door the other day. It was addressed to me from an anonymous person. I was about to throw it in the bin when I saw that it was addressed to Beastly Gerbil, not my real name so I realised it was a puzzle. It started off like this:

Someone is in danger, and you need to warn them. I can't say directly who in case this is intercepted so I have hidden it as a puzzle. Work this out and warn the person.

On the back was this:

23^rd July 4516 - CEDFCED - If you do in fool's rain down
23^rd April 7615 - DDAGAAF -Your condition that now slows a lie
21^st March 6547 - GBBGGGC - A ceiling is across it your ground
17^th April 6235 - CEDBBCE - Won't you find your shoes missing who
27^th April 6531 - EBBEBGD - Issue shallow wall whilst a about stop
23^rd June 5417 - AACFCFA - Your wall shadows knows you'll from my
26^th May 1734 - FFAGFDE - Is walking boots filling know suppose newts

Who do I warn?

Hint:

@Levieux is on the final step. Now you just need to look at the steganography tag. You are looking for a type of relative.

Answer 1

You should warn your

COUSIN

What got me started was this:

All lines can be split up in three parts, as the title suggests: dates, strings and "nonsense".
All dates contain the numbers 1-7 when written out, except 25-4-7615, but this might be a typo and should then (probably) become 23-4-7615.
Next are the strings, they all consist of 7 characters. They also all contain only letter from A-G.
Last part is the "nonsense". Every line of this nonsense is exactly seven words long.

Putting this together:

Most likely the numbers in the dates, together with the letters in the strings, tell us how to construct meaningful sentences out of the "nonsense".
The date numbers and their corresponding letters all form unique combinations, i.e. A-G are combined with 1-7 all exactly once.
We have:
2C-3E-7D-4F-5C-1E-6D
2D-3F-4A-7G-6A-1A-5D
2G-1B-3B-6G-5G-4G-7C
1C-7E-4D-6B-2B-3C-5E
2E-7B-4B-6E-5B-3G-1D
2A-3A-6C-5F-4C-1F-7A
2F-6F-5A-1G-7F-3D-4E

If you arrange the nonsense lines in a grid, like this:
Or like this:


Taking the indicated cells might be the solution, although I can't find anything meaningful in it yet..
I also tried sorting the lines by date (day and month) and by year and then applying the same logic, but this also leads to gibberish.

It looks like the beginning of each line is already (partially) correct, e.g. If you do, A ceiling is, Won't you find might well be the first word of meaningful sentences, so maybe we don't need to rearrange all the words quite as much...

Thanks to Piotr Pytlik:
If we now order all pieces (1A-1B-1C-...-1G-2A-2B-...-7G) we get:

A ceiling won't stop rain from filling
your shoes, if your issue is a wall is missing.
Suppose you lie about that wall,
you'll find newts in your boots, a fool's condition.
Who knows, it slows your shadows down,
whilst walking across my shallow ground.
Do you know now?

Now to figure whom this is about.

Thanks to OP's hint, I found: All letters preceding occurrences of the letter 'e' spell out the word COUSIN.
A Ceiling won't stop rain from filling
your shOes, if your issUe is a wall is missing.
SuppoSe you lIe about that wall,
you'll find Newts in your boots, a fool's condition.
Who knows, it slows your shadows down,
whilst walking across my shallow ground.
Do you know now?

Answer 2

Partial
23rd July 4516 - CEDFCID - If you do in fool's rain down

23 7 4516 (7 numbers) - CEDFCID(7 letters) - If you do in fool's rain down(7 words)

25th April 7615 - DFAGAAD -Your condition that now slows a lie

25 4 7615 - DFAGAAD -Your condition that now slows a lie

21st March 6547 - GBBGGGC - A ceiling is across it your ground

21 3 6547 - GBBGGGC - A ceiling is across it your ground

17th April 6235 - CWDBBCE - Won't you find your shoes missing who

17 4 6235 - CWDBBCE - Won't you find your shoes missing who

27th April 6531 - EBBEBGD - Issue shallow wall whilst a about stop

27 4 6531 - EBBEBGD - Issue shallow wall whilst a about stop

23rd June 5417 - AACFCFA - Your wall shadows knows you'll from my

23 6 5417 - AACFCFA - Your wall shadows knows you'll from my

26th May 1734 - FFAGFDE - Is walking boots filling know suppose newts

26 5 1734 - FFAGFDE - Is walking boots filling know suppose newts