If you divide the prices from the old editions by 10 you get about the current edition's prices. People's houses cost about their yearly income, and this seems to be quite accurate historically. He could perhaps "buy" (by giving gifts) land, and building labor and materials from a chieftain or a king, and go to a slave market to buy slaves. 2000L would get him a large house, two hides of land and slaves to work the land and serve him. His yearly income would be 80L. If he wanted to just get something built, a mansion from RQ3 would be 2400L RQG Lunars, so 2000L should be enough for a small temple.
Another way to handle the gifts would be to use the Loyalty Passions:
Gifts
For every 20 L given as gifts to another adventurer, temple, or other community, an adventurer may get a +1% bonus to a single Loyalty roll with that entity. For every 50 L given, the adventurer gets a +1% cumulative and permanent increase in that Loyalty.
So giving all that money to the local temple/clan/tribe would give him Loyalty (Temple/Clan/Tribe) 100% and +100% for his next Loyalty roll. You could also combine these methods and give him the Loyalty bonuses, and have some important NPC in your campaign give him a title and job like eg. the Thain of Apple Lane.