iPhone wi-fi grey not working

I take it you mean the " oven" to mean he put it in there to reflow the solder. If this made the wifi work great but it obviously wasn't a permanent solution! That would be re soldering the wifi chip which is on the back of the motherboard. At least you know the chip works, now you need to find out where the connection is broken and someone to sort it out . As for the charging? It may just be that you should check and clean all the connections especially no 4. If that doesn't help try a new dock, if that doesn't work then maybe the "oven" wasn't such a hot idea! Pardon the pun... Just couldn't help myself