Re: 85hp force 88yr
The oil you are seeing may not be gear case oil. Take your finger and dab it and smell the oil. If it has any gas odor to it, it's probably not gear case oil, but unburned fuel/oil mixture. Nothing to worry about. If it has a distinctive sulfur smell to it, then that's a different story. Gear case oil has a very distinctive smell to it.
Now for the "drain plug".
Sounds like your son removed the wrong plug. It sounds like he removed the shift linkage pivot pin. It's not uncommon to mistake it for a drain plug. Very difficult to get back in as you have to get the internal linkage perfectly lined up to go back in. Most of the time it's pretty much impossible to do. You end up having to take the lower gear case apart to get the pin back in.
The drain plug is located on the very bottom of the gear case. Towards the front bottom side of the gear case. Sometimes it's difficult to see it. It's probably an Allen head insert. You need an Allen wrench to remove it.