While I agree there's nothing wrong with an older man wishing to marry a younger woman, it's also true that from the father's perspective, the only reason he might consider the older man a good match for his daughter would be financial stability or overall maturity. These would have to outweigh the negatives like the possibility of the girl one day becoming a widow and still having young children to care for. It's not unreasonable that a father would prefer his daughter to marry someone her own age -- especially if he himself is financially able to assist them as the young man becomes more established. If he thinks she will have no problems finding a suitable mate her own age, he has every reason to disuade her from taking an interest in an older man.