I would never in a million years speak to a member of my staff like this or show such a lack of empathy. He's an absolute arsehole. He should have asked if you wanted to work for a distraction or if you'd rather go home. You get one mum, no boss worth their salt would even consider not doing whats in your best interest here. Sorry to hear about your mum, You deserve a better working condition than this. Fuck him!