I think it was on the cards for a while, we kept loosing fish for no reason, seemingly out of no where (water quality was excellent other than being a little hard). thb I wanted top re-stock, thinking about going shrimp and snail only.Sorry to hear that, I don’t let anyone look after my fish for this reason.
But I also like to go on holiday so I’m limited to stocking what can cope with being fed via and auto feeder (which is most tropicals in fairness), I’d definitely recommend one.
Sometimes if good to start over when this kind of thing happens, mix up the tank decor etc.
You can get away with doing a few big water changes over the course of a few days and restocking slowly but it depends on how bad the tank was when you got back to it.