Ex partner not taking care of child's health needs - neglect?

[RJFWells]

Advice needed please.

3 year old had regular contact with his dad but I have some large concerns of neglect and passing responsibility. He has admitted his other two children aged 13 and 11 sometimes get him up and sort him out in the mornings whilst he stays in bed, this resulted in him having cows milk for the first time in months after a cows milk protein allergy wad diagnosed. He has then spent the last 16 hours with me being sick and being wheezy. He had asthma also and I have explained before that cows milk aggravates his wheeziness. 8 weeks ago he handed him back to me in such a wheezy state that an ambulance was at our house 4 hours later and he was admitted to hospital. He doesn't attend any hospital appointments, asked him to help choose preschool and he didn't bother so still doesn't know or ask where his child attends. He doesn't ask me how he has been, what he has been doing or communicate in anyway. Child is currently being assessed for being on ASD and his response was 'I think he is just a git'. I am going to seek legal advice but after I have tried to speak amicably to this person and been sworn at I am very close to stopping contact as I believe he is not regarding or caring for his need appropriately. Please advise

This is very clearly a welfare issue... That you have proof of the detrimental effect on your child, which you have tried to sort amicably. So your options are q) keep contact as is and risk further serious ill effects to the child...
Or
B) stop contact explaing very concisely and in a calm professional manner via email and text and recorded delivery letter your serious concerns about the child's welfare and health concerns under the current arrangements / your attempts to rectify being rejected and ignored making contact unsafe for the child.
Parental responsibility requires a parent to ensure that their children are safe, if the other parent isn't and you are concerned that it will continue to be an unsafe situation then surely it's your responsibility to remove your son from the situation to ensure that he is not in an unsafe detrimental situation?

Thank you. I also think it is a total welfare concern and I want to immediately stop contact until legal boundaries and arrangements are out in place and agreed upon, I am just terrified of doing so and having him come for everything I have. He is a very narcissistic person and can easily sweet talk any person he meets, leaving them with a completely different impression to what he is. He scares me, not physically but because he knows how to make my life utter hell. Me telling him to make sure he doesn't give him cows milk in the future is me 'being an arse again' and 'I'll take you to court' if I say anything else. On the surface of it he appears to be doing everything a dad should- but he doesn't ask a single question about his child and he doesn't communicate a thing with me, so I have no idea how well cared for my son is with him and now he's lost any trust I gave him by returning him poorly. Just so scared of a court going against my favour.

I realise it's a catch 22 darned if you do and darned if you do nothing BUT there are health records / text messages emails that corroborate your concerns regarding your son's welfare / safety? Gather them together and order them in a timeline as this will show to a court (if he took you to court for a c100 child arrangements order) that you TRIED to arrange contact for the sake of your child - in line with his (your son's right) to know his other parent BUT that contact became untenable due to safeguarding and a risk to your son's health - your parental responsibility requires that you keep your son out of harms way and as safe as possible - within reason. Allergies are NOT to be messed with - as you know and by failing to take a responsibility for his sons health and safety your ex is failing in his parental responsibility.
But for your own sake moving forward it would be advised to only communicate with your ex by text or email (then you have an irrevocable record of communication) as you say he is liable to twist stories - much much more difficult to do if you have records? Good luck.