-He can come for the meeting and then go back to China to get the H1 visa. Thus, he loses nothing. Or just get the H1 visa in China, not come to US with B1.
If he use B1 to come US and change to H1, it is also OK but not good because his change of status in such a short time has a big chance to get denied.
Background: 这个工作机会是美国一famous研究所的staff scientist.另外, 他原来在美国待过(J1),因为J 不能豁免而回国, 现完成2年回国服务期,got his EB1a-140 approved.准备过来马上递交485