Advice on ABP appeal lodged by family member that I disagreed to

[Joint Executor]

The family home has been left in the will to myself and 1 sibling.
An application for the planning permission of a 3 bedroom home on the land was refused in March., on the grounds of piecemeal development and further objections.
The Architect was retained by my sibling without my input and I only received plans after they were lodged. I was far from happy with the quality of his work, a ridiculous fee for putting a generic house in the plans and made this clear to my sibling.
No surprise that it was refused. He then stated they were lodging and appeal with ABP. I completely disagreed and requested the house be sold as it stands with potential and also to view any appeal "Before" it was lodged.
I was notified by the Architect that the appeal had been lodged and that was as much information he was providing as I was not his client.
My question is, what can I do to stop this process and proceed with the sale of the property as it stands , with a great valuation on it .
Many thanks in advance to anyone who can help.

 

[Seagull]

Your sibling has no rights to make unilateral decisions. The problem is that forcing the sale of the house as it stands is going to incur legal fees unless you can get him to agree. Given that he has gone ahead with this plan against your will, he should be solely liable for any costs incurred.

 

[John Sipos]

Time to get a solicitor and start putting things in writing I think. Sorry you have such a difficult sibling.

 

[Joint Executor]

/Thank you to all for your advice. After threatening legal action on the basis of not adhering to the terms of the will, the house is now on the market at a great price. Thanks again, it really helped me.