Transfer of deeds Capital gains?

I really hope someone can help me with this as my mind is whirring. My brother kindly put his name on a mortgage with me 5 years ago to enable me to get my foot on the property ladder as I was self employed. He didn't contribute any deposit or mortgage payment and was on the mortgage and deeds in name only. He hasn't lived at the property but does use it as a postal address for a couple of things. I am now at the end of the 5 yr fixed mortgage and am in process of getting a remortgage (on the same property) solely in my name as I am now in a stronger financial place. My brother doesn't own his own property so is now keen to come off the deeds in order to perhaps by a place for himself too. No money is going to change hands between us or anything so my first question is around stamp duty and whether I'll have to pay it if he essentially just 'gifts' me his 'half' of the property? The outstanding amount on the mortgage which I will be responsible for is 105k.
Secondly, and more worryingly, will he be expected to pay capital gains tax? He only ever came on the mortgage to help me and as I said, I paid the deposit and all subsequent repayments. Any advice would be gratefully received as am having a real panic! Thank you!!