If you add a NULL into a string, the result is NULL, so you need to handle the nulls individually like this:

ISNULL(first value, second value) - returns the first non-null value. COALESCE can handle more than 2 values - I don't think you need this though.

So you would use:

Select ISNULL(Father_FirstName + ' ', '') + ISNULL(Father_LastName + ' ', '') + ISNULL(Father_Occupation... AS Parent

You only need to deal with the columns which contain nulls (of course).

Note: The way it's written stops too many spaces being entered in the string.