OK. So I did some research on the tax implication. According to the tax law 2022, as long as a non-US citizen is sending the money to my husband, my husband will only have to file tax if the annual accumulated amount of incoming transfers from oversea is over 100k USD per year. That said, my husband has been receiving 80k-100k per year already for school. So he will file tax if he receive that 150k cash gift for asset proof. Yet, he would likely not have to tax for that because the sender is not a US citizen. Another update, we have figured out to have his multiple relatives send the 150k total from mainland china to my mother in law's hong kong bank account. As my mother in law is a permanent resident in both Mainland China and Hong Kong, there will be no "legal" issues. So at the end, my mother in law will be sending the 150k in one go to my husband's US account so that my husband can file tax on this on one go as well. It might look less "fishy" as it would not be multiple 20k from multiple chinese relatives.