The advice from the controller regarding heavy precipitation and further advice to change course sounds very relevant especially regarding the initial loss of 1000 feet.
It sounds as if the aircraft hit a severe downdraught and stalled in the process.
A spin is unlikely to break an aircraft a spiral dive could do so.
It is possible with modern training methods to incipient that there was confusion over which state the aircraft was in and incorrect recovery methods used?
Whatever the aircraft was in a high rate of descent after the first loss of control enough to break it.
Advice to drop the gear beyond VNE springs to mind in beyond VNE dives?
With part of the wings and flying structures missing it was inevitable that a spinning motion would occur whether in a true spin or the aircraft not being in a balanced flying state.
A really sad disaster to a lovely family