Hi @Darren66
You’ll most definitely be able to find a good off-grid installer in WA (I certainly hope), but it’s a bit state, where abouts is your brother located?
We have a Perth solar page here with a bit of info. @Den_Thomson is in Bunbury I believe, and might be able to help or point you in the right direction.
With off-grid solar in particular, you do not just want to source the products, you want to get someone that really knows what they are doing to design the system first. There is a lot that goes into working out the best combo of panels, batteries and generator to make sure your have a well sized and reliable system.
If you can’t find someone who can do all that close by, you could potentially get someone else (anywhere really) to design the system, and have a more local electrician/installer install it.
Cheers
Marty