Cancellation of GST Registration

My friend received a Notice from STO . From Ist July 2017 To 15 Dec : 2017 he had a total purchase of Rs 1,09,000 . There is no sales during this period . He had not submitted his G ST returns in this period .
He closed his business from Jan:2018 onwards and disposed all the business Assets and Liabilities.. STO is going to cancell his registration . I would like to know what will be the financial Liabilities which GST is going to Imposs to him ?
please Guide me sir.