right thick black border at the end of the month and message on holiday code

[glda19]

I
In the file you see thick black border at the and of the month.
Now i have vba code to set the thick redlines.
The code redaw also the black line.
The question is how can i make that the border of the last week on the right is thick.

Second question. In the white cells under the date i set com codes so i can see when i take a day off.
one code is CV corporate holiday between the redlines whe have to take every tilme a day cv.
Ho can i give a message that the cv is not taken between the redlines