Soundproofing, reasonable adjustments and the autism and equalities act

Hello everyone I need advice on whether my nephew has been discriminated against under the Equalities Act 2010 or Auitsm Act 2009 by his local council. I did ask this on another genreal forum but felt no one really replied. So have signed up here to get some specialist advice.

My nephew suffers from autism, which causes meltdowns (anger outbursts) and self-harm in relation to sensory overload from noises.
His support worker contacted the council's adult and social care team to request an occupational therapy assessment to establish if soundproofing could help reduce noise and provide a safe space to go when needed. All adaptations carried out in this council area if you are a tenant there are free and do not require an application for a disabled facilites grant. An OT called back from the council today and explained that because his needs arise from a sensory disability and not a physical one, the funding policy for the revenue budgetdoes not cover soundproofing or sensory issues.

I'm understanding that autistic people are protected under the Autism Act and the Equality Act 2010 from discrimination against their disability, regardless of whether it is physical or not.

Could anyone provide any insight as to whether this is true or if the Council has the legal right to decline an OT assessment?

A big thank you in advance to anyone who can help shed light on this situation.