My 2 cents
IC: You better remember that in Roesone you serve the people of Roesone and their lawfully apointed and divinely enthroned ruler, Aruvor, not the family of Isilvieres
OOC: Historically, the medieval clergy kept their ties with the family and used their clerical assets and powers to further their dynastic interests and hurt the enemies of the family. However, bishops and abbots perceived their territories as "theirs" and "God's," not as goods to be distributed to the family. A bishop was just as greedy to get his hands on as much land and castles as possible to use for his own needs, like building bigger cathedrals, purchasing better relics than his peers etc. Of course, some money would/could be sent to a brother baron, or diplomatic aid could be provided (mediation in feuds, for instance or a good word with the ruler), but outright donations of large amounts of property and/or income were not that common, both because the bishop needed his assets to "succeed" in his clerical world and because there wasn't a shortage of ambiitous underlings willing to send word to Rome that the Lord's assets are being embezzeled. True, there is no Pope in BR (well, you're your own Pope, sort of, and the Pointiff is mostly a titular ruler
but this is a setting where clerics cast spells and gods can be somewhat meddlesome (and Bjorn will concoct all sorts of nastiness if you abuse your position hehe). I had problems with my own clergy as HA when they thought I was straying from the orthodoxy and dealing too much with IHH so its safe to assume that your clergy (who are also members of various noble families) wouldn't take kindly to you lavishing your relatives with "Haelyn's property."
That still doesn't mean you shouldn't be favorable to them, of course, but you should know and weigh all the pros and cons, especially in this game.
As I said, my 2 cents as a player.