Nope, less than 100 bucks for a replacement EPROM. 2nd hand ECU is more than 500 bucks. AUDExactly! The F4 ecu seems the same of Brutale but are not the same inside, to change the chips inside will costs more that to change ecu directly.
Anyway to insert a brutale engine on f4 frame it's a meaningless thing when the price of engine are almost the same. Also, if you're not expert, to insert a different version engine will give many problems. On F4 frame must insert a F4 engine, He has a first generation of F4 750, so could insert a f4 engine from evo1 until evo3 750cc. After that version or different version (brutale ndr) have to change ecu, also elettronic and elettric things (much difference).
Everything is possible but will cost more that to insert the proper engine.
This is the realiity, the owner can choose if to accept the advice or avoid it.
For sure if he inserts the proper engine will not regret it