Offshore software development has become a huge industry over last 30 years. Your friend can find a company or a team in almost any country that is close in culture and offer good price/value ratio. There are some do's and don'ts in this process, but he can find them on Internet easily. The most dangerous underwater stone to mention is intellectual property rights, especially when you do not follow all regulations. There are many others as well. I am in offshore software development for 25+ years and worked with USA and European clients, learned a lot of cross-cultural hints. Your friend better find someone who can help him in choosing the vendor and establishing relations with it.

Hello. No one has experience in estimating unknown work. There is plenty of effort estimation methodologies and they all are not exactly correct. You can use one of the methodologies used with Agile. Like the one when the team gets together and each member has a card where he/she writes her estimate and puts card face down. Then when everyone is ready cards are opened and members with biggest and smallest estimates explain their numbers and team discuss. Then you repeat the cycle with cards, and repeat it until all numbers are the same or very close. There are other methodologies, but this one is very popular. You can Google for "agile effort estimation methodologies" or like this.