I use BlueWallet for hers. It’s not a huge amount so I feel relatively secure keeping it in a hot wallet. If she gets a lot more or if Bitcoin moons then I will probably move it to cold storage and create a sub account using Sparrow wallet. 


https://sparrowwallet.com/docs/coldcard-wallet.html#adding-an-account 

 A hot wallet is nice because I can easily show her what it’s worth. But I realize there’s a security trade off there.