Королевой был снижен брачный возраст

The queen was reduced the age of marriage, and she entered into a registered marriage at the age of 16. A year later, she broke up the marriage due to the rude attitude of her husband and decided, together with her one-year-old son, to change his place of residence.
She sold the country house presented to her by her grandfather for the wedding in order to buy an apartment at a new place. The grandfather, having learned about this, filed a lawsuit in court to declare the contract of sale and purchase null and void, since the Queen is a minor and cannot independently conclude transactions with real estate. At the same time, he asked to appoint himself as the trustee of his granddaughter, and to oblige her to live at the place of residence of the trustee.
What decision should take a court decision? Justify the answer.

After payment you will be available a link to the solution of this problem in the file of MS Word. It should be noted that the problem solutions put up for sale were successfully handed over in the period 2003-2018 and could be outdated. However, the general algorithm will always remain true.