@Eaudeunaturale: I think the only things you can do, as @tangledyarn says, is reassure him that you understand how bad he feels but that he will get better soon, and provide him with as many distractions as possible. Computer and console games, cartoons, familiar stories, perhaps audio books? Cuddling up on the sofa or in bed to watch a favourite film together? And then all of the physical things to alleviate symptoms that people have tried on the earlier threads - lots of water, warm drinks, hot water bottles, warm showers. Is he cold as well as shaky? When I was most chilled I needed piles of duvets, shawls, jumpers and hot water bottles. I wonder if weighted blankets, or heavy piles of bedding might help with the shakes for your and @TheDrsWife46's DC?
It's so hard when they are ill and I know you feel so powerless.