My daughter is has dyslexia and dyspraxia, I asked her and this is what she said
In the long run paying for the assessment is worthwhile. Don't rush to do it if you can't afford it.
As your DS had an assesment does he think he will be able to cope with out the adjustments it gave him?
In terms of DSA equipment it varies according to who is assessing you and what they recommend.
I had 2 done because I started in medicine and did an intercalated degree. Both courses were almost identical in terms of requirements but what I got was so different!
Laptops
1st one- No laptop you are not entitled to one its not an additional requirement as a result of disability, all students need one
2nd assessment- yes laptop+ printer and scanner+headphones
I chose to upgrade my laptop so I paid £460, in total for the surface pro laptop, a canon mg3650 and some headset thingy,
Printing allowance
1st assessment-£200ish for consumables
2nd assessment-no consumable allowance
1-1 tutor
1st assessment-42 hours per year
2nd assessment- 15hours a year
Travel
1st assessment- paid for some travel to uni to use the libraries/printers(if i remembered to return the receipts)
2nd assesment-no travel