When we look at someone's outer appearance and notice that they look like their parent or sibling, is it their dna we are seeing?

Combined things: Family members look alike mainly because they share similar genetics (DNA). What we see is the biological expression of their DNA, because DNA itself are too small to be seen. That being said, we also see similarities because family members might eat similar foods, have similar haircuts, use similar make-up styles, share similar habits, talk using similar patterns, etc. Many things are familial.