When a Muslim brother sneezes, he will say الحمد لله ( Praise be to Allah ) and it is the duty ( Voluntary ) of another Muslim to say يهديكم الله ويصلح بالكم ( Yahdeekum ullahu Wa uslih Balakum ) It means May Allah show you the right path and keep you in right condition. It is one of the Islamic Etiquette. استغفر الله means " I ask Allah's forgiveness. ( Asthagfirullah )

shokran jzlan= شكرا جزيلا means = Thank you so much shokran jzlan= thank you so much استغفر الله= Astakfer Allah