Different standards

I feel bad writing this but it’s starting to really stress me.

Background:
DD2 and Son in Law are both self employed and work around the 2 children. This means that three evenings a week she leaves the house to go to work and he looks after the DGC. I look after youngest one day a week (non nursery day) so that DD can work.

Their house needs lots doing to it but they don’t have the money to get it finished (his parents and I have both lent them money to get a lot done but I have no more to lend them now)
Daughter feels frustrated by the house and hates staying in with the children due to this.
So she takes them out most days (when not at school/nursery)
Both parents are very laid back and I feel they are very fair with the children.
Both children are well adjusted and very loved. They have lovely family weekends together (days out, visiting friends and family etc)

But:
The house is always chaotic and disorganised. The toys have batteries that don’t work, or have parts missing.
The children are bad eaters despite the parents cooking decent meals.
Just to get them to eat something they end up full of sugar and processed foods.
We suspect eldest is dyslexic. DD knows he needs extra attention but isn’t around much to give it, or they are out doing things.
Eldest is also (in my opinion) on his PlayStation too much when at home.
DD says she limits screen time but I have my doubts.
There’s always washing up to be done, washing to be done/put away, the garden is a state due to losing grass during building work. They are disorganised.

I help a lot as I totally understand that parenting and working is hard. I did it single handedly for years.

I go round and help when I can. I fix the toys, take washing home and financially support them when I can. I do one on one stuff with the children which they love. They are always very grateful and happy for the help (I do check they are happy for me to do so)

They are all beautiful people. The kids are polite and gorgeous (biased I know) and both DD and SiL work hard to provide for their family.

DD suffered a breakdown 18 months ago and I obviously helped even more, looking after the children and doing housework when she was at her worst. She recovered well with therapy and medication.
And this is the main reason that I keep my mouth shut as I would hate to send her spiralling again.
It was probably around this time that I started to realise the chaos and disorganisation.

The other day, DD sprung the news that she is pregnant with DGC3.
I knew she always wanted 3 and she has had trouble conceiving in the past so I am happy for her and obviously congratulated them both.
But deep down, my heart sank a bit. She was very unwell with both pregnancies and I worry for her health. I worry that another baby will add to the chaos. I worry that DGS1 will have even less attention regarding his difficulty with school work.
But as well as all the worries, I also feel VERY guilty for being so critical.
We get on so well, see each other a lot and talk most days.
I sometimes ‘drop’ my worries into conversation and she is receptive to advice but there’s only so much I can say before I drive her mad!

Am I just an interfering old bat that needs to keep out of things, or are my worries and stress justified?

Be honest - I can take it