Want to extend wifi into guest house off of orbi Satellite using nighthawk EX7000

My parents built a 5,200 square foot home. 2 story, and i agreed to do all of the networking and home automation for them. I went with Comcast 100mbps for the internet speed, to power a Netgear CM1000 which is connected to an Orbi Router with 2 satellites. The Router and Modem are in an equipment room, and the satellites are on opposite ends of the home, one upstairs and one downstairs. 

First let me mention, that the wifi speeds on the satellites is not what i was expecting with the 100mbps internet speed. While standing at the satellite upstairs, probably 50 feet total away from the router, i am only getting around 15-20 mbps download and 11 mbps upload. 

My parents have a guest home about 30 feet behind their home. I get a wifi signal from the orbi satellite in the home, but the connection is to weak and i am not able to use the internet there. would a Netgear Nighthawk ex7000 work for extending the wifi into the guest home?