Any advice on what I should do about my bestfriend and her relationship with a guy who seems not to really care much about her????

So July of last year, my bestie (33yo) started dating a guy (33yo) that seems be be very selfish and inconsiderate. I, nor her family, have not met him yet and she lives with her parents. ( mind you it's almost been a year and he still hasn't had the time to meet any of us.) So almost a year in the relationship and he still takes forever to text her back. Always seems to make excuses and cancel plans. It has been a week or so since he last spent time with her and before that it was almost 4 weeks. Ok, he does have the excuse that he did purchase a house in December 2018 and he is constantly "working" on his house. I completely understand that it takes time to remodel a house but he usually tells her that he is busy with that and never seems to text her a quick, I'm busy right now and I'll get to you in a bit. So she ends up waiting hours for his response, when she texts him. And the same thing when he goes to work. Which again I understand when you are at work you can't text as often. But besides that they have not said the Love word yet. And she always seems to text him first and sometimes she feels like she texts him too much, just because he doesnt respond to her first text. He doesnt really say anything affection like you're beautiful or I have to see you or i just needed to hear from you. He has only said the occasional i miss you, here and there. And when they see each other she always seems to have to go to him. And hang with his friends. So overall I feel like this guy is just not that into her but why is he still holding on and making somewhat of an effort to keep her around besides the obvious. Anyone have any advise or should I just stand on the sidelines?? I just hate not knowing what this guys angle is. If you have any questions let me know.