Recommendation Spanish lawyer for contentious estate

Our client is the sole beneficiary of his brother’s Spanish estate pursuant to a Spanish will. The brother had been domiciled in Spain for a considerable period, but following a stroke in June 2022, the sister moved him to Italy (where she lives) and it appears she managed to be appointed as his attorney. The brother’s Spanish home was sold, following which the sale proceeds were quickly transferred from the Spanish bank account to the sister and her family. The brother died in Italy a few months later - funds (which appear to be UK pension deposits) regularly continued to be withdrawn from the Spanish bank account for two months after his death. It doesn’t appear that any of the bank transfers to the attorney and family were recorded as gifts so we are hopeful that they can be treated as loans that form part of the Spanish estate. We are also hopeful that the brother continued to be a Spanish domiciliary as he only moved out of Spain for medical treatment.
Can anyone recommend a Spanish lawyer who could advice on the nature of payments made pursuant to a power of attorney and who can also assist with action to recover funds?
Lee Harris, Martelli McKegg, New Zealand