Thank you for your question
My name is Clare
I shall dd my best to help you but I need some further information first
Where would the child live if you took over his care?
How will you arrange ongoing contact with his mother?
What I meant was - if your son moves to live with you what arrangements will you make for good ongoing contact between him and his mother
If you wish to change the current arrangements then you will need to apply to the Court for a Child Arrangement Order AND Leave to remove the Child from England and Wales.
The Leave to remove applictaion will not be straightforward and you can find out more about them here
Given the long term health problems that his mother has - and the clear impact on your son, there is an excellent chance of success - although I would offer Skype rather than phone calls
Please ask if you need further details
The fact that he visits you does not change the need for Leave to remove.
You can certainly instruct a firm to deal with the applictaion - one near where your son currently lives would be wise
It is likely to take between six and nine months - and cost will depend on where the hearing takes place and which solicitor you choose.
You are most welcome - I hope all goes well
The long history will work in your favour
Hard to say on costs
Between £2000 and £5000 as a very rough guide