Kindly explain why type 2 FIR filter cannot be used to design high pass filter.
Type 2 filters are even and symmetric. A signal with a frequency of $f_s/2$ is just a scaled version of
That means, at $f_s/2$, the response of a type 2 filter will always be zero as the coefficients of the same magnitude are an even number of samples apart so they cancel each other out.
A filter with a magnitude frequency response of zero at $f_s/2$ makes a very poor high pass filter.