Hello Please can someone advice when is the best time to buy BCH and what is the possibility of BCH price going up to meet BTC
Never, slim to none.
Or, no one knows.
Agreed nobody knows what is going to happen with coin but if you believe there is chance of comeback than you can buy at current price. That is free money that is the reason everyone is dumping his coin which is crashing this so badly.
Actually Roger said that he is willing to move all the hashrate (and every support he got, probably that includes selling his bitcoins) he has from bitcoin to bcash, if bitcoin don't get 2mb blocks in November.
Since he is a scam artist, he probably won't do it and there is nothing to worry.