Tahlia needs to be able to use Proloquo2Go on her own iPad so she can model AAC during Fletcher's sessions — but adding her to Apple Family Sharing isn't appropriate (it shares too much: purchases, billing, subscriptions). The goal is full app access on her device, using a license you already hold or can easily extend.
1. AssistiveWare Hub — Communication Partner access
AssistiveWare's Hub system lets you add caregivers and educators as communication partners linked to Fletcher's profile. Depending on the subscription tier you're on, this may grant Tahlia full app access on her own device under your account — without any Apple Family involvement. Worth checking your Hub account settings first before doing anything else.
2. Contact AssistiveWare directly
This is the most likely to actually work. AssistiveWare knows their app is used by NDIS-funded support teams across Australia. They have a history of offering free or heavily discounted "communication partner" licenses for support workers. One email explaining the situation (NDIS-funded support worker, 3hrs/wk, needs the app for AAC modelling) may solve this completely.
3. NDIS funding for a second license
Proloquo2Go for a support worker directly supporting Fletcher's AAC use is arguably "reasonable and necessary" under Capacity Building — Communication. If the Change of Circumstances comes through or at the next plan meeting, requesting a second license for Tahlia is worth adding to the list.
4. App Store sign-in for just the Store (not iCloud)
On Tahlia's iPad, she can sign into a different Apple ID only for the App Store (Settings → [her name] → Media & Purchases → View Account → Sign Out, then sign in with your App Store Apple ID). Her iCloud stays as hers — only app downloads use your account. This is technically within Apple's framework and doesn't require Family Sharing. Slightly fiddly to set up, and Tahlia needs to be comfortable with the change.