My dd was 4 when she was first diagnosed with leukaemia. As others have said, it is tough as I am sure you know from your experience with your mum, am so sorry you have to go through this again with your ds. I was working full-time when dd had to go through 2 years of chemotherapy. We had no help in the beginning, we thought we could cope. my lovely bosses agreed to let me work from home (and hospital which was most of the time). i don't know how i did it. all the other mothers just stopped working. after a while dh decided that we needed a live-in nanny so he hired one after i struggled for a couple of months taking dd to chemo almost every day, she also needed to be warded on many occasions, both for overnight chemo and also when she came down with fevers and infections for weeks at a time, I also had to clean vac and mop the house everyday whilst working (since their immunity is compromised by the chemo, the house needs to be really clean and free from dust and mould). We also needed a nanny for the times when I had to go out and could not bring dd, as she could not go to public places or even school for most of the two years. and i didn't even have another baby at the time to juggle with!
as for the social aspect, i feel that it is very important for them to play with kids their age to keep their spirits up, but you need to ask the doctors if they allow your ds to do so. i took calculated risks the first time dd had leukaemia (she has had it twice now), and let her play with her cousins and friends whom she was very close to, and only when her counts were good and they were in the pink of health. no coughs or colds or fevers or diarrhea or suspicious rashes. i took her into her old kindy once or twice cos she missed her teachers. her teacher even had a birthday party in class for her once. i just made sure they knew she couldn't be around sick kids. her doctors now are very strict this time though (we are at a different hospital as we are in a different country now) and she has just had a transplant so they have completely banned her from seeing any kids under 12 until after she passes Day +100. So somehow I have to try my best to keep her happy and entertained!! I was worried she would get clinically depressed in the beginning but she seems fine now. she kept crying in the beginning. I keep things positive, and we talk about how she will play with her cousins and friends once she is all better, and how we will go to Legoland, on holidays, that kind of thing!
When I first posted on mumsnet about dd's leukaemia in 2009, somebody recommended this book for dd. do have a look, i thought it was pretty good and simple. www.chemo-to-the-rescue.com/images/newbook/cover.html
The hospital that we are in now (National University Hospital in Singapore) has amazing play therapists and social workers, they have lots and lots of books and leaflets for kids, explaining all about cancer and chemo, and they have dolls with hickman lines attached, so that kids can play with the dolls and understand what a hickman line is.
Sorry this is really long! But pls do come over to the Cancer Kids thread whenever you need to...
for you.