SO is too harsh with our son but wont listen when I bring it up

Burn accountSo my son is almost 21 months, terrible twos come early i like to call it! Hes your usual naughty toddler, goes for plug sockets, tries to climb tables, tries to open front/back doors (can even turn keys), but hes also a good kid, puts his rubbish in the bin (sometimes without asking), helps when getting dressed, tries to help with the washing, and goes to sleep without a fuss. Bit of a greedy guts and will have a tantrum if you dont give him whatever food he sees, even if its in your mouth (stolen a biscuit out of a kids mouth before), but at least hes not a picky eater, and will sit and eat nicely at the table.SO is a SAHD but I only work 3 days, the rest of the week DS is all mine and he only watches him if I have an appointment or something important, otherwise he goes off and does his own thing while im home.However, I feel like my SO is too harsh with him, when hes naughty he will get up in his face and have a go at him, if im there DS goes quiet and looks over at me with a very sorry look while SO is harshly telling him to look at him while hes talking. He shouts at him just for having a tantrum, which I know is the only way he can express his anger/upset/emotions, but he gets scolded for it. As soon as SO raises his voice DS goes quiet and sits/stands still looking very sorry for himself.At bedtime he sleeps in the same room as us since we're living with my parents and theres no extra room. So I put him down in his cot and he turns to face the wall and I put his blanket over him, however if he tries to roll over or even move his arm SO will roughly lie him back towards the wall and tell him to keep still and go to sleep, which he does then stay still but I feel like thats only out of fear of getting told off again. Its the same in the morning, when he wakes he stands up and SO will snap his fingers and tell him to lie down, so he will stay led down quietly until SO or myself (on my days off) get out of bed otherwise he gets told off for standing/sitting.Ive tried bringing this up a few times but SO just responds with 'I will parent however I want to'. Now SO had a pretty abusive childhood, but he thinks it made him a better/respectful person, as if hes justifying the abuse. I had a spoilt childhood but I still had respect for my parents, I did what I was told, if I couldnt have something we compromised, but I didnt have to be beat in order to earn their respect.I dont really know what to do, he wont listen to me when I say hes too harsh, but I dont want DS to grow up scared of his dad. Advice much needed.Edit: Thank you all for the comments, Im in work right now but when I get home I will pull him to the side (my parents will be happy to watch DS) and he will listen to everything I have to say whether he likes it or not and I will be hard on him. via /r/Parenting https://ift.tt/2Moic2Q