My friend is a sahm and has 2 dcs.
Her dh works shifts and often the leg work falls to her.
He dd (3) is terribly shy and takes time to get to know people but once she does she's very bubbly and loves to have fun and play.
There's a group of mums at the nursery who are a good bunch there's regular meetings in the park, nature walks and birthday gatherings etc and me and my friend are always invited.
We met at the start of the week and friend left abruptly after less than an hour just got up and went everyone was 
There's a meet up this week where we're meeting in the local park having a picnic and letting the dcs play. Friend was going up until tonight now she's sent a message saying she's not going anymore no reason given.
She constantly moans she has no friends who can make mutual arrangements with her and spend time with dcs together, I do things with her on a small scale but I work so am not around much.
One mum has commented in the group that she's declined everything this year and joked that maybe she just doesn't want to come and we should stop asking her.
I can't help thinking she's not doing herself any favours and should make the effort to build a social network, the children from this nursery go to 2 schools in the local area so her dcs will be with at least 50% of them will be in her class in primary