How to display True & False for 1 & NULL
SQL Server does not have the Boolean data type. There are no built-in values true and false. One alternative is to use strings 'true' and 'false', but these are strings just like any other string. Often the bit type is used instead of Boolean as it can only have values 1 and 0. Typically 1 is used for "true" and 0 for "false". It is still an integer type, though. Boolean logic will not work. For example, if (CONVERT(bit, 1) and CONVERT(bit, 1))... is not legal syntax.

Likely the best option is to use a CASE and return the requisite strings, as @Akina commented:

CASE
    WHEN TheColumn = 1 THEN 'True'
    WHEN TheColumn IS NULL THEN 'False'
    ELSE 'Oops!'
END