In any marriage, the husband would have the final say on such matters.
Saying that, however, doesn't mean that he can morally make any decision on such matters without regard to his family's needs and desires. While a wife must submit to her husband, a husband is commanded to love his wife as Christ loves the Church and be willing to lay down his life for her.
Is the man described in the opening post making such purchases with his wife and family in mind, for the good of their souls and for their temporal well-being now and into the future? If not, he has seriously forsaken his duties to his family. If he has good reasons, he needs to communicate them to his wife so that she can understand why these things are necessary for the family at this time so that there will be peace in the family and the wife will know her husband loves her.
I would never make a "major financial" decision without my wife's input and, preferably, her approval, not because I am required to have it, but, rather, because she knows why I am doing as I am doing and she knows that it is for the good of the family. Ultimately, the responsibility for those decisions is mine whether the outcomes were positive or negative. But, in the end, she still knows I did my best for her sake and not for selfish pursuits.