I just saw how hard it made life for everyone around her and wondered why she had a third child (two I could understand more)
While I do appreciate the picture you paint of a working parent with disabled children under immense pressure and struggling with work obligations (and how this impacts colleagues), I do think the above comment is a bit simplistic.
Not everyone gets to make an informed choice about having a third child in the knowledge that they already have two disabled children.
Not all children are diagnosed in infancy or even in childhood. Sometimes their challenging behaviour is attributed to all sorts of other factors (childhood trauma, other disabilities, poor parenting, etc) for years before a full diagnosis is reached. Some women are in controlling marriages and don't have the ability to control their body or pregnancies.
Many people plan to raise children in a seemingly solid relationship but then that relationship ends (often as a result of the additional stress in this kind of situation) and then the mother has to go out to work when she had expected to be a carer in a two parent family when her DC were born. Other people are widowed.
Some people plan to rely on family support or standard childcare arrangements and it only becomes clear once their disabled DC are starting nursery/school (when the other DC might already be born) that this isn't feasible and that they will need specialist care. Also, family who are more than willing to help out with an autistic baby/toddler often find it increasingly challenging to provide the same level of practical childcare support as the child grows bigger and stronger, and as they diverge further and further from their peers in terms of independence. It's very difficult to remember to picture life caring for an aggressive adult-sized autistic teenager when you're looking at a cute baby that just has a few quirks and milestone delays.
There are all sorts of reasons why this mother might have had the third child without having deliberately signed up for being a working mother with three disabled children.