Is it permissible for a woman to manage her deceased husband's company, in which non-mahram men work, for the purpose of preserving her daughter's money and future, or does the mixing with men necessitate her leaving the company to avoid Allah's wrath?

The wealth of a deceased husband is a right for his heirs, who include the wife, children, and parents. Allah Almighty says: "Allah instructs you concerning your children: for the male, what is equal to the share of two females. But if there are [only] daughters, two or more, for them is two thirds of what he left. And if there is only one, her share is half. And for one's parents, to each one of them is a sixth of what he left if he had a child. But if he had no child and his parents are his heirs, then for his mother is one third. And if he had brothers [and sisters], for his mother is a sixth, after any bequest he [may have] made or debt. Your fathers and your sons - you know not which of them are nearer to you in benefit. [These shares are] an obligation [imposed] by Allah. Indeed, Allah is ever Knowing and Wise." [An-Nisa:11]

And He, glorified be He, says: "And for the wives is one fourth of what you leave if you have no child. But if you have a child, for them is an eighth of what you leave, after any bequest you [may have] made or debt." [An-Nisa:12]

The Prophet, peace and blessings be upon him, said: "Whoever leaves behind wealth, it is for his heirs."

Since there is a minor among the heirs, it is best to go to the Sharia judge to inventory the heirs and divide the wealth. The share of the infant daughter should be placed in the hands of a trustworthy guardian who will develop it for her and spend on her as is customary. The adult heirs can leave their shares as a partnership among themselves and agree on who will manage it.

A woman's work that involves mixing with men is not permissible except out of necessity. Therefore, a trustworthy person should be sought to do the work, with monitoring and supervision from home without her presence and mixing with men.