Search Results: i'm ignoring her

So there's this guy that I have always had feelings for
We had abit of history in the past
But he's recently came back - he been messaging me first whenever Im online at night

He asked me how I am, what Im upto and sometimes being a flirt

But thing is:
- he texts me whenever we are BOTH online at night (11pm+)
- we both work during daytime but Im always online and he's mostly online at night

Sometimes I would ignore his flirty texts just to play hard to get and not sure of his true intentions
But he would always try to text me again whenever he sees me online🤷‍♀️

Is this a bad sign that he only texts me at night?
Is he interested? In what way?

Me and this guy used to date back in college..6 years ago
But nothing too serious
Even after I left, we still have each other on facebook - he never deleted me
Even when I got into relationships..
But now im single

So recently he came back into my life
He messaged me
And so we talked back and forth sometimes about whats goin on in our life
I am still attracted to him and have a soft spot for him in my heart

He kind of flirts with me
But sometimes I forget to text him back/ignored his message
And he would still try messaging me again

Why does he do this?
Guys, would you do this?
Or only if you're interested in her?

So I've met this guy 4-5 months ago and since begining acts different than other guys in our group of friends. He had problem talking to me, he was staring at me a lot and smiling, when I would ignore him standing next to me he would become mean and stuff.. and always was near me wherever i stand. Last 3-4 weeks he's been really distant in person.. he would smile anymore, won't stand near me and other stuff he did, but he always wants to help me. We have group chat with two more guys, and my guy friend said that him and I text almost always in there. We tease eah other, he compliments me and we sand each other hearts sometimes (most are between us).

So few days ago he called me on app and me and my friend didn't answer and he said that we should give him our numbers and i sand it to him in private box. After two hours he texted me and I tried to continue conversation but it died quickly (I have his number for month and he has mine but he acted like he forgot about it and he sent me text). He stopped to talked on wapp and answer to my text on group chat from few hours ago and i ignored it. I ignored him for 3 days and today I tagged his friend and asked him something and this guy answered in second for friend, and he did it twice.. and he wasn't even online when i sent message in group chat.

I don't know what's whit this guy. I think he might be like me but im not sure. Two weeks ago we were for 5 minutes alone first time and he was so quiet until his friend came and i don't know why.
He's nice guy, but I don't know why he won't talk to me in private box or when we are alone. He's really sometimes weird. What should I do?