Although not exclusively a problem for single parents, it can be hard on them if they are working full time - have to collect other children from school, nursery, etc, and manage the whole show themselves.
I only had one child as a single parent - but was working as a 'temp' which sometimes meant extensive travelling to bookings far away from where I lived, travelling by public transport. I then had to collect my son from the lady who picked him up from school and cared for him until I arrived, often having to shop, too.
I always managed to help him with homework, but there were times - because I was also studying - when I really could have done without the hassle, especially if it was a subject in which I was not particularly 'fluent'. This was in the days before the world-wide-web.
I didn't lead a chaotic lifestyle, but I'm not sure the educational authorities really understand that family life can be, and that we don't all live in a semi-detached with mother working part-time (or even SAH), living an ordered life centred around our children. I had no family nearby and everything that involved our family-life was down to me, including repairs of failed equipment and that sort of stuff normally undertaken by the other-half.
But, at least, I was permanently employed on a good wage, with secure work and no need to try to find extra work to toggle on to existing zero-hour contracts. So from that angle, and it was one I am now eternally thankful for, there was no stress; no interviews with Job Centres or social services, or tedious forms to keep filling out. And, I had secure accommodation with a reasonable rent. So from that perspective I was relaxed enough to be able to focus my attention on my son's education, because I didn't have all the extra stressors that so many appear to suffer today, which makes helping with homework sometimes appear just like another added stress.