Dynamically update the column name in SQL

How dynamically update the column name in SQL inside the case statement.

DECLARE @CNT INT=1

DECLARE @COL VARCHAR(15)='RM_TGT' + CONVERT(VARCHAR,@CNT)

DECLARE @Heading VARCHAR(25)=NULL

WHILE @CNT<=12

BEGIN

IF (@CNT=1 )

SET @Heading='TARGETS(S): '

ELSE

SET @Heading=''

UPDATE [DenaliConversion].[dbo].[RM_CAFILE_MO_FACTORS_NEW]

SET CUSTOM_TEXT_01 =CUSTOM_TEXT_01 + CHAR(10) + @Heading +

CASE

WHEN @COL='01' THEN 'ANIMALS/LIVESTOCK' + ', '

WHEN @COL='02' THEN 'AUTO PARTS' + ', '

WHEN @COL='03' THEN 'CASH/NOTES' + ', '

WHEN @COL='04' THEN 'CLASSROOM EQUIPMENT' + ', '

WHEN @COL='05' THEN 'CLOTHING/FURS' + ', '

ELSE

@COL + ', '

END

SET @CNT=@CNT + 1

END;