Well,besides the spelling mistakeĀ 'theee' instead of 'three', this sentence seems to be GRAMMATICALLY CORRECT.
Also as had been laughing is the PAST PERFECT CONTINUOUS formĀ of the verb to laugh
1 3 1
  • Brainly User
Had should be changed into has. According to me the sentence should be : He has been laughing for last 3 minutes
1 3 1