Can someone please help me? My cat ate an Ibuprofen tablet!!!?

My parents refuse to take it to the vet, it doesn't seem to be harmed at all except it seems a little nauseous... I've made sure it eats and drinks a LOT to dilute the toxicity, but I don't know what else to do. Don't say take it to the vet, 'cause I swear, they won't take me point blank! Will the kitty be okay? It was only one tablet. What can I do to help? I think it's too late to make it barf, it ingested it last night. :(