Disclaimer I am not a lawyerB2 visas are generally not sponsored so unless you really know what you aredoing like you are an immigration lawyer I would suggest not to sponsor.There are a few exceptions but those would not apply for friends.The best approach is to make sure the friend can show by himselfherself theirnonimmigrant intent their ability to support the cost of the trip the tiesto their home country and intent to come back. For that most people located in the USA will not be of help except forproviding an invitation to stay for a limited time as the address the friendwill prfor their short stay. Family supporting the trip for examplewould be much more helpful if they reside in the home country than in the USA. If you both are single and may be interested in dating for example yoursupport would be counterproductive.