Canon Law makes it clear that the competent authorities must be involved in this, just not simply the parish priest and the local parish.
Contracts and especially Alienation (Cann. 1290 - 1298)
Can. 1290 The general and particular provisions which the civil law in a territory has established for contracts and their disposition are to be observed with the same eVects in canon law insofar as the matters are subject to the power of governance of the Church unless the provisions are contrary to divine law or canon law provides otherwise, and without prejudice to the prescript of can. 1547.
Can. 1291 The permission of the authority competent according to the norm of law is required for the valid alienation of goods which constitute by legitimate designation the stable patrimony of a public juridic person and whose value exceeds the sum defined by law.
Can. 1292 §1. Without prejudice to the prescript of can. 638, §3, when the value of the goods whose alienation is proposed falls within the minimum and maximum amounts to be defined by the conference of bishops for its own region, the competent authority is determined by the statutes of juridic persons if they are not subject to the diocesan bishop; otherwise, the competent authority is the diocesan bishop with the consent of the finance council, the college of consultors, and those concerned. The diocesan bishop himself also needs their consent to alienate the goods of the diocese.
§2. The permission of the Holy See is also required for the valid alienation of goods whose value exceeds the maximum amount, goods given to the Church by vow, or goods precious for artistic or historical reasons.
§3. If the asset to be alienated is divisible, the parts already alienated must be mentioned when seeking permission for the alienation; otherwise the permission is invalid.
§4. Those who by advice or consent must take part in alienating goods are not to offer advice or consent unless they have first been thoroughly informed both of the economic state of the juridic person whose goods are proposed for alienation and of previous alienations.
Can. 1293 §1. The alienation of goods whose value exceeds the defined minimum amount also requires the following:
1/ a just cause, such as urgent necessity, evident advantage, piety, charity, or some other grave pastoral reason;
2/ a written appraisal by experts of the asset to be alienated.
§2. Other precautions prescribed by legitimate authority are also to be observed to avoid harm to the Church.
Can. 1294 §1. An asset ordinarily must not be alienated for a price less than that indicated in the appraisal.
§2. The money received from the alienation is either to be invested carefully for the advantage of the Church or to be expended prudently according to the purposes of the alienation.
Can. 1295 The requirements of cann. 1291-1294, to which the statutes of juridic persons must also conform, must be observed not only in alienation but also in any transaction which can worsen the patrimonial condition of a juridic person.
Can. 1296 Whenever ecclesiastical goods have been alienated without the required canonical formalities but the alienation is valid civilly, it is for the competent authority, after having considered everything thoroughly, to decide whether and what type of action, namely, personal or real, is to be instituted by whom and against whom in order to vindicate the rights of the Church.
Can. 1297 Attentive to local circumstances, it is for the conference of bishops to establish norms for the leasing of Church goods, especially regarding the permission to be obtained from competent ecclesiastical authority.
Can. 1298 Unless an asset is of little value, ecclesiastical goods are not to be sold or leased to the administrators of these goods or to their relatives up to the fourth degree of consanguinity or affinity without the special written permission of competent authority.