I am 37 yrs old, married, and we live comfortably.?

My best friend of 25 yrs has never dated anyone...EVER. She recently began seeing this guy (met online) and he is 38, lives w/ his parents and has a VERY small (and failing) business. I feel this guy has found my friend and latched on to her because SHE is successful, has a house and a nice car. The problem is that she is NEVER around anymore. She spends all her time with this guy and hardly even talks to any of her friends anymore.

The other day I told her how I felt and she got upset. She said that I was being unreasonable and harsh on her. SHe said she does not feel like she spending too much time with this guy (of course she says that) Then told me that if my comments continue to be negative, she no longer wants to be friends. Well that stopped me from telling her REST of my concern which is that this guy is just using her to be able to move out of his house and other advantages. I said nothing more except that I was sorry if I upset her.

I have decided that I am not going to even ASK about this guy anymore and I guess she is going to have to figure this out on her own. Am I doing the right thing?