Civil engineering solution.home construction.column footing

My friend is constructing his home...he will make two columns to support his 14ft * 20ft and 4.5 inch terrace slab...he started with 1.5 sq ft concrete column from bottom till NGL, and 4.5 inch brick wall around the column..with only 4 bars each of 12mm...he plans to reduce the thickness of column to 1 sq ft from NGL till the slab...even though the soil underneath is very hard I personally dont think its enough...i am looking for a solution now...what can be done to make the base more strong without demolishing his previous work

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