The Prophet sallallaahu 'alayhi wa sallam said:
‘If you see something from your brother, yourself or wealth which you find impressing, then invoke blessing for it, for the evil eye is indeed true.’
you may say:
Allaahumma baarik 'alayh(i)
اللهم بارك عليه.
'O Allaah, send blessings upon him.'
Maa shaa Allaahu, laa quwwata illaa billaah(i)
ما شاء الله، لا قوة إلا بالله.
'(This is) that which Allaah has willed, there is no power except with Allaah.'