Use any major US bank if you really want to send big chunk of money to Nepal. Make sure you send dollar from here. Not Nepalse currncy. They will give you low exchange rate here is US if you transfer nepalese currency. So just ask them to send dollar to Nepal. And when it gets there , you get the echange rate which is the buying rate of dollar in nepal. The exchange rate is higher than moneygram western union or any other thirs party services. You might end of paying $45 fee to intiate transfer from here through bank but trust me you will save a lot on echange. This is my personal experience. Done this many time and never had any issue. No suspicious report no legal issues. Just indicated reason as family support while doing wire.
I want to suggest one more time, send dollar from here . Do not intiate echange is US. They will ask if you want to send dollar or local currencies and go for dollar.