Deputyship and potential sale of a property

Husband and wife own their home as tenants in common.

Wife is in a care home and lost capacity . Son wishes to apply to become her Deputy.

Husband has made a lasting power of attorney appointing son and a replacement attorney. .

Husband will continue to live in the house.

At some point the house will need to be sold. Looking at the Deputyship notes on joint ownership it advises that an application can be made if there is an existing owner of the property un s36(9) Trustee Act 1925 or is a deceased co owner under s 54 Trustee Act 1925. Obviously I don’t know under what circumstances the house will be sold under. Do we just need to apply for the Deputyship first and then make a further application when the facts are known?

Thank you for any help