This depends on your budget and the local atmospheric conditions.
Looking on eBay, Altelix (a Florida-based reseller of gear sourced from Alibaba suppliers) has a good selection of directional parabolic wifi antennas. Alfa also sells these. You'd pick the gain you feel is necessary, and pair them point-to-point. 5 GHz is more expensive, but those go up to 30 dBi if not higher. 2.4 GHz would probably be fine since you're making do with a shared connection that's only 50/50, so on 40 MHz channel widths SISO, 60 Mbps throughput is probably a good average for what you'd get at zero attenuation. Just get the right connectors between his wifi router, jumper cables, and an indoor/ceiling antenna on your end. You would need to mount the parabolic antennas with line of sight.
You can't do an Ethernet run because its maximum cabling length is 328 feet. You could add two Ethernet extenders to cover the distance if you can run power cords to each extender. MoCA wouldn't work because the attenuation is more than 75 dB at 900+ feet, although preamplifiers might give you a workaround.
Or you could run LMR-600 cable between your friend's wifi router and an antenna in the third wheel. That's about $1 per foot, though.
A consumer range extender wouldn't cover the distance. The free space loss at 900 feet would be at least 90 dB, so your wifi RSSI would be below -65 dBm, which is why you need high gain parabolic antennas for a very narrow beam width with line of sight between the antenna pair.