let us dissect your question,

Two brothers own a piece of land jointly, of which one is 16 years old, both brothers execute a GPA and JDA with a builder to construct apartments, if you buy a flat in this project is it safe as it involves a minor.

At the time of purchase of land one brother was a minor rep by his guardian, whether that guardian is the other brother must be ascertained, if not then the guardian must have been his mother or father.

Next both brothers executed the GPA & JDA in favour of builder, after the minor has become a major, it is advisible to take a Deed of Confirmation from the minor, who has attained majority confirming the execution of GPA & JDA when he was a minor to over come any future problems.

If the mother has signed on behalf of the minor, then it is legal and binding, however as suggested it is advisible to get executed a Deed of Confirmation from the minor, on his attaining majority, with the builder confirming both the GPA & JDA to avoid any future legal hassles. Get this document duly registered also.

minor has not yet attained majority . bank has refused to sanction you loan on said ground that GPA is executed by minor . you had raised this query earlier too wherein we had advised you not to buy the property

One of the owners of the land is a minor. Execution of GPA by the minor does not authorise the sale of this property inasmuch as the GPA can be revoked by him. It is on account of this reason that in reply to your verbatim previous query I had advised you not to buy this property.