Delayed flight, missing connecting flight, now what?

My friend is flying from Hartford, CT to San Francisco, CA. First leg is delayed by 4 hours, they will have missed their connecting flight to SFO at Chicago MWD.

So what happens now?

Thanks

In my experience, the air line will set you up to get to where you were going. Might be a day late, but you will get there.

Yeah, and they may, or may not cover accommodations depending upon the cause of the delay.

Yeah, it’s happened to me any number of times. If at all possible, they will try to get you on a later flight the same day, sometimes via another route or carrier. If not, they may put you up in a hotel and send you on the following day. Whether or not they pay for the hotel and meals depends on whether they regard it as their fault (equipment problem) or not (weather delay).

What happens if I miss my connecting flight?