I don't think there are any biblical prohibitions against older men begetting children, but there are reasons for prudence identified by modern medical experience which morally licit medical technology may be able to overcome. Talk to a priest and to a Catholic doctor. Perhaps someone from an NFP clinic will be able to give sound technical advice.
Children, and children to be, should be protected against foreseeable physical and emotional stresses, such as ill health, and early bereavement caused by the death of a parent. Ideally, a parent shouldn't be dying until their children have reached an age at which they should be emotionally independent (mid-20s?), and, these days, it may be good for a grandparent to hang around long enough for their grandchildren to experience the love of two generations at least until they are post-teen.
But the aesthetics are important too. Children have been born at the darkest of times, collective and personal, as a sign that the light of the future can never be extinguished, because God is, among other things, the future. Women are said to be saved by childbirth. So too, possibly, are men.