An employee who receives sick pay is taxed on it. It is treated the same as other taxable compensation, which means it is taxable for income tax purposes and subject to FICA.
Employers who give sick pay to an employee can deduct the payment. Again, it is merely another form of taxable compensation.
Generally, an unmarried person who maintains a household for dependents and is allowed to compute his or her tax based on head of household rates, which are more favorable than single person rates.