Hi Sorry I can't offer more than a sympathetic I know your pain story. My DS had a similar reaction (twice) to a liquid medicine for a gut parasite while we were living in Ghana. He had to have the medicine three times a day and for about 2 hours after each dose he would go completely mental it was not at all fun. We really dreaded the evening dose...
I don't know what it was that did it but it's only ever been that medicine that's caused such a reaction for him.
I second the suggestion to ask the pharmacist to see if maybe you can work out what the culprit could be so you can better avoid it in the future.
Also I'd reckon crushing up tablets could be a better option. I'm pretty sure my DS was reacting to something they used to cover up the (absolutely awful) taste of the medicine rather than the actual medicine. You could probably talk to the pharmacist about doing that actually since they often have the powdered form themselves and could make up correctly dosed capsules for you.
Good luck! I hope everything calms down soon. And that everyone is better in your house soon!