Mothers don't necessarily want to solve their difficulties with small children by going back to work, especially if at the end of it they spend out so much on childcare that it is hardly worth doing moneywise. All that means us you are knackered with the job and you will need to fit in all the domestic chores and somewhere in there a relationship with 2 little children.
I'm sorry to say that what you say is not helpful. Don't make light of her difficulties, how would you feel if someone did that to you. Many grans forget what it was like to have small children 24/7, it is really hard. She is not wallowing in the awfulness of domestic life, she is living it 24 hours a day and with little prospect of help from a hardworking husband, so she is no doubt shouldering things that in an ideal world he would do.
Things will improve and we survived, well yes terribly patronising and unhelpful, sorry
Yes things will improve. Think what you'd want someone to say to you if you were in a difficult situation, would you want people to say, gosh how difficult for you,a situation like that is bound to make you feel upset, or for someone to dismiss your feelings by telling you it will get better. Why not try saying something along the lines of motherhood is nothing like the adverts, It is really really tough, being responsible for 2 little children 24/7 is so relentless, you can't switch off for a minute even when they are in bed you always have half an ear on will they wake up. That opens communication not shuts it down. If you do want to get in a bit about improving, then something like maybe its hard to think when life is so overwhelming that sometime in the future things will get better, when you are surviving day to day. Yes, we survived but that again not helpful. She will survive, yes, as you survive other difficult times, but again it comes over as less than helpful. Do you ever gently say how happy the children are, how responsive she is to their needs, how good it is to see them being so well looked after, how wonderful that she is still breastfeeding, how that is such a worthwhile thing to do for her children's health and happiness.
I'm sorry that she says things that upset you, even when they are true. My children are both adults, and compared to when they were little I have so much more time to do what I want even though I work part time, I volunteer, I have animals and have to visit my very elderly mum at the other end of the country. If I can organise my responsibilities, ie get on top of work, and ask my daughter to look after the animals I can have a day out, or a few days out, I can do the household chores and no one but me messes things up. I only felt that overwhelming feeling of complete responsibility last year when mum was in hospital and I looked after dad who by then needed 24 hour care.
She may well be depressed, but feeling understood and listened to can be really helpful, and if she feels she needs help from the gp or the local wellbeing service she can get it. She can still breastfeed on medication, so no worries on that front. Finding a local breastfeeding group can be helpful, if there is one locally. Meeting up once a month with other mums and being listened to in a non judgemental way can be so helpful. She will see other mums all struggling in different ways , and finding different solutions based on their own situation, if she goes to meetings regularly she will see mothers who felt overwhelmed when she first met them but now things are easier, which will give her hope.
It is so important to not give advice, this is usually what worked for you, but she is a different person with different children and a different home life, it will not necessarily be the right thing for her. If you can see something that might be helpful you could say something like some mothers find x is helpful but others find y helpful. Or if you had a magic lamp what 3 wishes would you ask for And never criticism. Her choices are not a criticism of your choices all those years ago, and will have been carefully considered
Its great that you are so open to exploring other ways of helping her, she is lucky to have someone who wants to be supportive