Lol whatchu talkin about Alex. I'm sure he knows that, but his talking about possibly buying a house with a friend and having the title 100% in his friends name and the consequences.
Anyways, Birds does raise a good point re what happens in unforeseen circumstances if one party wants 'out' or can no longer service the mortgage. Shit may get complicated.
In any case don't have the title 100% in his name. If he decides not to honour it in the end and not give you your share, your going to have to go to court and you will have headaches. Even if you have the legal paperwork in place in will be up to the discretion of the Judge to interpret the case.
So yeah if you go ahead with this, have the property in both names and sort out the legal paperwork so you mate gets his deposit back on sale of property.