Just like any other aircraft, balloons are required to fly above 500 feet (above ground level), except when taking off and landing. They also have to maintain 1000 feet over any obstacle within 2000 feet, horizontally.
As long as they are doing this, they are legal. "Property rights" don't include the air above you.
[Note: balloon festivals get a waiver of these rules, with certain pre-requisites]
He appears to be about 4620ft WSW of the alignment approach to NW end of runway 12 at Thermal airport about 2.75 miles away. He is well within the 20000 ft Surface zone for the approach (about 16000ft) and Elev -29 ASL,..Airport Elev of -115ASL.
IMHO, the airport was there before he was and he should have investigated before he invested.
Regarding the nearby Thermal CA airport,...from Wikipedia...
“The facility hosts an air show in late November, showcasing both full-scale aircraft and radio controlled models as flown by members of the Coachella Valley Radio Control Club. Due to that club’s proximity to the facility, both the club and the airport work closely in mid-January to establish no-fly zones for the club’s “Best In The West” national jet rally. A temporary model operational ceiling of 2000’ (610m) is established during that time due to the size and speed of the models which participate.”