Ladies in the uk

Sorry for the long post but PLEASE PLEASE PLEASE keep reading! Ok so as well as trying to convince our first child together I have a step son who I have mentioned on here before and who I adore (most of the time- he is 7) anyway he has an extremely lazy mum, naw I don't begin to say that I am the tidiest person alive but my house is clean and not a tip (lived in) her house is disgusting from what my step son tells me and what I can gather for myself from the front door, the smell is pretty terrible! Anyway my biggest concern is that I think my stepson is being neglected, my husband picked him up last night and he had his school report wich was not great it say he only completes homework sometimes (when he has been with us for the weekend) he is behind on all subject but maths where he is just keeping up (he used to be ahead in maths). He was dirty when he came to us, I saw his fingernails and assumed he had been doing messy activities at school but he informed me that he hadn't had a bath since he was at our house (2weeks ago) when I was washing his hair in the bath I noticed that his private area and between his legs was very red and sore, I asked him about it and he said he thinks it's because sometimes he doesn't have any clean boxers (he doesn't have the best aim when going to the toilet so sometimes his pants get wet so obviously not having clean boxers every day is awful) I really don't know what to do because if I report her and she knows it's us she will make things difficult because it has taken us ages to get to this amacable stage, I just want him with us so we can show him what life should be like and not just every other weekend! I have stayed annonsmous as I know it is very unlikely but I wouldn't like this to get back to her! Am I being rediculous?