Is a father considered sinful for refusing to marry off his 17-year-old daughter to a 41-year-old man, given that the other conditions are met (religious commitment, good character, financial capability), due to the significant age difference?

The father of the daughter has the right to refuse to marry her to someone he does not deem suitable, and there is no sin upon him as long as his refusal does not harm her, or if she was content with him. It is preferable that the refusal is not merely due to an age difference, as an age difference is not considered a barrier to marriage, neither legally nor naturally. The criterion is piety and character, based on the Prophet's (peace be upon him) saying: "If someone whose religion and character you approve comes to you proposing marriage, then marry him. If you do not do so, there will be tribulation on earth and widespread corruption."