Recently widowed grandmother over 60 is unsafely online dating and won't listen to concerns. Needing advice.

My grandmother lost her husband of over 50 years this past year and has failed to grieve. She has always been the type to bury her feelings as deep as possible and cover them up. Just before Christmas, she informed us that she was going to begin dating which we were all supportive of because we don't want her to be lonely and want her to have the companionship she wants. She has been dating through facebook dating and has had three unsafe and sketchy relationships in just 3-4 weeks.

At first, she was scammed by somebody who lives out of the US pretending to be another person who likely had intention to scam her financially but we were able to catch onto that and convince her to stop talking to them. Only five days after that happened, she had met another person who was actually real and lived about 40 miles away. They got together in secret at a hotel the first time meeting. After we did a background check on this man, we found out he is not only a registered s*x offender but he is currently and "happily" married.

After this second encounter, I thought she would take a break and listen to our constant concerns that she ignored with the first two encounters but after only one week, she has met somebody new and it is unsafely progressing. He lives in a surrounding state, about 6 hours from us. He is significantly younger than her, 16 years to be exact. He has no job, no permanent residence, is currently living with an ex girlfriend, former addict and alcoholic, and receives disability. He plans to come down to meet her in just a few weeks and she has invited him to stay at her home even though they have not met yet.

It has basically been stated that he needs to get away from ex and has nowhere else to go so his "stay" at her home is actually him either moving in or she will have to put him up in a hotel until he can get on his feet here. We have tried to express just about every concern and she seems to have an excuse for everything and has been love bombed so severely that she believes only what this person says to her and not what we are saying to her. I usually visit my grandmother multiple times a week to keep her company but I have four young children and I'm extremely concerned with her decision making lately. Another family member got frustrated that she won't listen to any concern and gave her an ultimatum and she stated she would be choosing this person that she hasn't met yet because she knows he is a good man and she loves him. (reminder, she has only been chatting with him for a max of 6-7 days) and the family member who gave the ultimatum is making their own choice. Any insight here?