If your husband's maternal aunt sold the house to him or give it to him for nothing, and he took possession of this gift and it was under his control throughout this long period, then the house is your husband's property and he can dispose of it however he wishes, by selling it or otherwise. And he may sell it and gave the money mentioned to his brother or to his aunt's daughter.
The husband has to fear Allah and should not refuse to ask scholars about anything he is confused about, because Allah says (interpretation of the meaning):
So ask of those who know the Scripture, if you know not [al-Nahl 16:43].
We ask Allah to help and guide us and you.
And Allah knows best.
Reproduced from Islam QA