Mortgage advice - relationship split after 3 months

[AdviceforDGDplease]

Posting for advice for my goddaughter, with permission, long time poster, have name changed.
Having been with her bf for almost 4 years, they bought and moved into a house together 3 months ago. He has ended the relationship suddenly. She and her parents are devastated, and are unsure what to do re the house. I know they will need to speak to the mortgage company but that won’t be until Tuesday. I said I could ask on here to see if anyone involved with mortgages or who have been through similar can say what the options are and they agreed.
Goddaughter can’t afford the mortgage on her own but wants to stay in the house and is happy to take in a lodger. The parents have had a fairly recent inheritance so could buy the ex boyfriend’s half, and the daughter pay them back via income from lodger once she has one. He has said he will continue to pay his half meanwhile. Well he has to really.
So I guess it would effectively be a remortgage but not sure if that is allowed so early into a mortgage agreement?
As said, they will speak to the mortgage provider next week but that seems like so far away to them that any information from those who know this area well would be appreciated, to start to understand what the possible options are. Thank you.

In theory there’s no reason they can’t do this, but be prepared for the fact that there is a fee to pay and after only 3 months that fee will be really quite substantial.

Also factor in that she would need to be able to get a mortgage in her sole name, so worth doing the numbers to see what is possible, most lenders go with approx 4x income then factor in any debts to check affordability, and she can’t use the potential future income from a lodger in there.

It wouldn’t be a remortgage, it would be an entirely separate one in her own name.

Thank you @Mrsttcno1 very helpful.

The title and mortgage would need to be transferred to her as sole owner. She could probably keep the same mortgage terms and use the funds from her parents to make an overpayment (which would incur an early repayment charge - most mortgages allow overpayments of up to 10% per annum so the ERC would be on the extra 40% assuming she can cover 50% of the mortgage). It depends on the bank and the terms of the mortgage. Either way, as they are not married, she might have to pay stamp duty on the transfer of his share to her.

Similar happened to me but after a month! I kept the same mortgage but needed the deeds changed which was about £700, 20 years ago.

Thank you all so much.