Python to write multiple dataframes and highlight rows inside an excel file
First, starting from your code, you should realize that you are repeating yourself, three times. This goes against the principle Don't repeat Yourself (DRY).

The only real difference between processing your three sheets are their name and the underlying dataframe, so you could make this into two functions:

from win32com.client import Dispatch
import pandas as pd

def highlight_false(df):
    arr = (df.select_dtypes(include=[bool])).eq(False).any(axis=1).values
    return np.arange(1, len(df) + 1)[arr].tolist()


def color_rows(sheet, rows, col):
    for row in rows:
        cells = f"A{row+1}:{col}{row+1}"
        sheet.Range(cells).Interior.ColorIndex = 6
    sheet.Columns.AutoFit()


if __name__ == "__main__":
    Emp_ID_df = ...
    writer = pd.ExcelWriter(OutputName)
    Emp_ID_df.to_excel(writer, 'Sheet1', index=False)

    excel_app = Dispatch("Excel.Application")
    workbook = excel_app.Workbooks.Open(OutputName)
    excel_app.visible = False

    sheet_names = ["Sheet1"]
    dfs = [Emp_ID_df]
    for sheet_name, df in zip(sheet_names, dfs):
        sheet = workbook.Sheets(sheet)
        rows = highlight_false(df)
        col = colnum_num_string(df.shape[1])
        color_rows(sheet, rows, col)


However, there is an even easier method using xlsxwriter:

import pandas as pd

Emp_ID_df = ...

writer = pd.ExcelWriter(OutputName, engine='xlsxwriter')
Emp_ID_df.to_excel(writer, sheet_name="Sheet1", index=False)

workbook = writer.book
format1 = workbook.add_format({'bg_color': '#FFC7CE',
                               'font_color': '#9C0006'})
dfs = [Emp_ID_df]
for df, sheet in zip(dfs, writer.sheets.values()):
    nrow, ncol = df.shape
    col_letter = colnum_num_string(ncol + 1)
    cells = f"A1:{col_letter}{nrow+1}"
    sheet.conditional_format(cells, {"type": "cell",
                                     "criteria": "==",
                                     "value": 0,
                                     "format": format1})
writer.save()


You might have to ensure that the sheets do not get out of snyc from the data frames, or just keep track of what name you save each dataframe to.

In addition I used Python's official style-guide, PEP8, which recommends using lower_case for functions and variables as well as renaming your variables so they are a lot clearer.