Using Nizoral (ketoconazole) shampoo helps person suffering from alpoecia?

Possibly. There is data to suggest that male pattern alopecia may benefit from use of ketoconazole topically, although not approved for usage by fda. Currently only approved usage is for dandruff and seborrheic scalp dermatitis.
Ketoconazole. Ketoconazole is used to treat infections caused by a fungus or yeast. It works by killing the fungus or yeast or preventing its growth. If it is alopecia due to seborrheic dermatitis then you are using it for the correct reason. If you are unsure, you really should ask the doctor who prescribed the medication.