No, the aircraft is owned 50% by each 'owner' in a company structure. One of the 'owners' removed the director of the company (another person) and appointed himself as the director of the company (whilst the other owner was in hospital having open heart surgery).
There is due process to follow for change to office bearers in a company. Has a Power of Attorney been abused?
Unfortunately there is not a detailed ownership agreement.
Presumably you are both shareholders in this Company setup?
Good luck, this looks like a feeding frenzy for lawyers. Hope you find the aeroplane.