Translation:कौन देखता है?
Did you perhaps mean to reply to me? (Your comment is at the top level, and the question's given translation - देखता है - doesn't indicate any plutality.)
I would suggest that 'who' can be either. 'Those who choose to...' refers to a plurality of people; 'He who....' refers to one (male).
Some general comment like 'who sees' is in English more ambiguous: 'who are the people' or 'is there anyone'. When you translate to Hindi, you have to make a choice. If in doubt, I suppose, go plural - it can't be wrong, worst case you're conveying surprising respect/formality.