--hardy requires many individuals to judge deviation from Hardy-Weinberg equilibrium. Single-individual .hwe files will not be useful.
If you are trying to perform quality control on samples, consider plotting top principal components (computed with EIGENSOFT 6, or plink --pca) and removing extreme outliers.
VCFtools has the function
--het such as
vcftools --vcf input.vcf --het --out output.het
Calculates a measure of heterozygosity on a per-individual basis. Specfically, the inbreeding coefficient, F, is estimated for each individual using a method of moments. The resulting file has the suffix ".het".
Check the full manual: https://vcftools.github.io/man_latest.html
Check this post if you have difficulty to interpret the results: Is the heterozygosity flag (--het) in vcftools calculate observed and expected heterozygosity?