If the house was in joint names only a death certificate will be needed and then probate will only be required if there are assets in the deceased own name that are either: real property (land, houses etc) or substantial bank accounts/life policies or similar. There is no one amount that qualifies as "substantial" - for some institutions its c.25K but for the post office for example its about 8K.
If she hasn't had to get probate so far and if the house is in joint names she probably doesn't need it. But to be sure she should consult a solicitor.
If she hasn't had to get probate so far and if the house is in joint names she probably doesn't need it. But to be sure she should consult a solicitor.