Hi, my name is Colettewilcox!

Hi @Colettewilcox and welcome to this community.
In my opinion this is one of the hardest realities facing parents; the aging process that effects both parent and children along with 'how will my children cope' when I'm no longer here'.  This is true for parents of disabled & non-disabled children.  

I know my mother is no longer able to assist in all my needs - she tries, and equally I try to make sure I don't need her to do those things.

There are practical elements in your post -  For these you may need to consider contacting Social Services : Adult Care Services if you are struggling to assist your son NOW; you may receive help NOW.

I have no idea the level of disability that your son has, but it might be worth considering writing a Lasting Power of Attorney.  I'm listing two links
LP12 Make and register your lasting power of attorney: a guide (web version) - GOV.UK (www.gov.uk)
How to be an attorney - GOV.UK (www.gov.uk)

There are emotional elements to your post also - I am sure there will be local groups to discuss & share experiences. If you would like me to find out more please reply and add @JustPete in your post so I get to see it.

I hope this helps a little, but please do not hesitate to post again.

Sending you best wishes
Pete