There are ways to helppeoplewith LD keep their famillies-when I was at a related charity a group of volunteers took on a family with 2 children they were going tolose, giving them 2 hours a day plus extra focus time on weaning, food etc,and help to access toddlergroups and the like.
The family thrived.
There will always be a few peopleunable to care for their kids becuae of LD but there are solutions for most- even down to the offer of palces in hostels where famillies are assusted by live in carers. Sometimes it is easier toremove though i think, but proactive approaches are possible.
You are worried about them with their own children when they're grown? I know of a family where Dad has autism ( I assume he is high functioning because I only noticed once I'd been told IYSWIM) 2 sons are on spectrum also... one has very little speech and stims constantly. As far as I am aware SS are only involved in offering respite and support. They are not in Birmingham though.