Unusual Remortgage - any issues around tax?

Hi all, long time lurker, new poster here. Hopefully someone can advise.

I'm about to carry out a rather unusual remortgage. Nearly 5 years ago my father lent us the money to buy our house to help us get started on the property ladder (very fortunate position to be in I know).

We are the legal owners of the property and our name is on the deeds and my father is essentially our mortgage lender. We have now come to the point where we agreed we'd remortgage with a 'regular' mortgage lender and pay my father back.

I'm just wondering how the transfer of the money actually works once the remortgage goes through? Does the new mortgage lender put the funds in my bank account and I have to then transfer it to my father (and if this is the case, are there any tax implications?) or do I just provide the new mortgage lender with my fathers bank details and they stick it straight into his account?

The other point is that my father wants to lend the money straight on to my brother to give him the same help. Would it be better to see if the new mortgage company can transfer it straight into my brothers account or would that not be possible?

Any help greatly appreciated.