What's the benefit for parents (and family, related) if letting children go forth, become monks?
In traditional countries, to give high beloved like ones children into the Sasana, dedicate them for the Tripple Gems, is said to be of high merits for the parents and family?
How can the benefit be understood, explained, in regard of the Dhamma-Vinaya?
At a festival for the dedication of the Great Pataliputra monastery called the Aśokārāma as well as the other viharas built by Ashoka, Moggaliputta-Tissa, in answer to a question, informed Ashoka that one becomes a kinsman of the Buddha's religion only by letting one's son or daughter enter the Sangha. Upon this suggestion, Ashoka had both his son Mahinda and daughter Sanghamitta ordained (Mhv.v.191ff.).
Supposed a society, family..., group, is not at all delighted to give (up) their children for the Sasana, does not approve the going forth as praisworthy, could such a society, nation, be ever related?
[The question is also related to What is meant by the impossibility “A Buddha can not help someone not related to him”?, see also Do Buddhist children outside of Buddhist countries ever become monks?. Related question in regard of particular fruit: Where did the belief about monks' mothers going to heaven come from?]
(Note that this is not asked for trade, exchange, stacks, entertainment and akusala deeds, but as a share of merits and continue such for release)