Questions on Visitor's visa - Urgent !!!

[Hitech Guy]

Folks,

My father is planning on visiting U.S. in the first week of June - primarily to travel the New England area. He has a 10 year multiple entry visa. He was in the U.S. last year for 6 months and left to India in Feb.2003. Before that he was here for about 4 months in 2002 and he never extended his stay.

1. What documents, if any, do I need to send him to show at the POE ? Do I need send him an invitation letter even though he has a 10-year multiple entry visa ?

2. Is there going to be any problem at the POE, since he is returning within 3 months of his last visit (Also, my mother is not joining him this time) ? What possible questions can he expect at the POE ?

3. He is also flying into Boston (I live in Dallas) as he is initially going to be staying with my uncle in Maine for a few weeks. How does this affect the docs I need to send ? Do I need to send any proof-of-address docs from my uncle or does it make sense to ask my uncle to send an invitation letter instead of me ?

4. What address should he use on his I-94 form (mine or my uncle's) since he is going to fly into Boston instead of Dallas ?

Any input/thoughts in this matter are greatly appreciated.