Are you sure that they cannot be put on the deed? We move a lot and sometimes we have gone through the process of including me on the mortgage and sometimes we haven’t (I don’t earn any income, so I am not making an impact on approval for the mortgage). But, I am most definitely always on the deed. For example, we closed on this house a yr ago and I had had my credit locked when everything was going on with the leaks last yr. I had trouble unlocking my credit from all 3 of the credit reporting agencies within the time allotted on our contract. Only 2 unlocked in time for the mortgage approval, so the mortgage company refused to include me on the mortgage. But, I am most definitely on the deed.
Whether or not that is what you actually want to do is a different question, but I would investigate further if you want their name on the deed without being on the mortgage. A financial planner would probably have better insight as to what is the best way to approach this scenario for the long-term.