Trouble getting gy-neo6mv2 serial data with RS232

[Art]

And I misspoke when I said I had connected the module to an RS-232 port... it's a serial port on a 10+ year old computer using windows 98

That’s almost certainly an RS232 serial port with typical 12 Volt signal, and 24 Volt swing,
and it occurs to me you misspoke when you say you connected the GPS rx pin to the computer, or you wouldn’t see anything if the ports were compatible!
So if you have only connected your GPS tx pin to the PC serial port rx pin, I don’t suppose there’s a problem in terms of damage, but surprising you see anything on the terminal.
So check the 628 data sheet for what voltage is a logic high for the pic input pin you use as GPS receive, and I think you’ll find it’s below 3V.
Fine if you only want to receive data from the GPS, but if you want to configure it with the pic it will be a different story,
and you will want to level shift the pic’s 5V serial transmit output to the 3.3/3.6 V or whatever it was for the Ublox.
The standard NMEA is present for default configuration, so you might not need to ever change the default configuration.

I haven't connected a Ublox to a PC, but the sentence format is exactly as specified in the data sheet.

If you can connect the 628A to the PC as in the manual, you might as well do that.
If using PBP software serial read the ublox data into a big array, then you have the rest of the second to spit the array to the PC.
If using hardware serial on the 628A, you should be able to read a byte and if a byte was received, transmit a byte (in a loop).

You want something like 100 byte array or a little less to receive everything the Ublox will spit out by default,
probably larger than the maximum array, but IIRC, all of the good stuff comes first.