Do whirl wind romances ever result in a strong, long-standing relationship?

My daughter is 28, has never been married, but has always yearned for a family. She has 4 kids, ages 1 yr (twins,) 8 and 10. She met a guy at the beginning of December on a dating website. I’ll call him Pat. He’s 30-something. They began talking on the phone and exchanging texts.

On their first date, just before Christmas, she fell really, really hard and from what I can see, he’s fallen just as hard. I’ve met him several times, exchanged messages on fb, and I like what I’ve seen so far, but they’re talking marriage, like NOW. She’s moving about 70 miles away at the end of Feb to live with him.

She’s met his mother and his blind aunt (who he helps care for,) and stayed with them over a couple of weekends and she tells me they just think the world of her and the twins and she thinks the world of them.

Part of me will be relieved that she’ll have someone in her life to back her up, and I won’t be the sole go-to for everything she needs help with (that gets exhausting,) but part of me is terrified that I’ll get a phone call in a few months asking for help.

I’m really scared you guys. And kind of depressed right now. It’s not like she’s moving across the country but still….any reassurances any one can give me?