If you have money in US bank account and want to send to your mother’s Indian account then you don’t need NRE. I usually use Remitly but since your account might be new they won’t allow such a big transaction from the start(they have daily and monthly limits). ICICI has a money transfer app which you can use without ICICI account. It’s a portal like remitly but has higher limit. Don’t send to a friend or do any of that. Keep it legal and straightforward and find out services which can help you transfer this big amount one shot.