Bedroom tax, if outhouse converted to bedroom and bathroom

Good morning,

Newbie here...hope I get this right lol.

I live in a three bedroom HA property with my two adult children.

After a recent OT assessment we are trying to get out outhouse converted to a bathroom and possible bedroom for me, as due to disability the stairs are a danger.

If this is approved, I will have one extra bedroom upstairs, will I have to pay bedroom tax even though the conversation will be done due to disability?

My sons bedroom in very small so he would move into my current bedroom. I think he’s current bedroom is just too big for us to try to get exemption due to the size sadly.

I am aware of DHP but this is only short term and I am in no position to pay bedroom tax.

Thank you