Can you help reassure my friend for me?

Hey all, Irish student studying law in the UK here! I'm not asking for legal advice, my friend is going to consult a solicitor and I'm confident, based off the facts that it'll be an easy case for him, I just want to reassure him that he is innocent.

A few weeks back me and a few friends from college went out on a night out back home and one of the lads came back home with a girl. The girl went up to him first and also asked to take him home with her. My friend was obviously intoxicated, this lass less so and he agreed. I chimed in and said that he wouldn't know the way back to mine if he went with her, and she then offered to come back with us. Anyways, after they came back they went into the guest bedroom, and in the morning she took a bus back home after we had breakfast. She was in a cheery mood then.

Turns out shes now accusing my friend of rape, claiming that he took advantage of her when she was drunk. I was there to witness the whole thing, he was significantly more intoxicated than she was and it was her that offered to go home with him. My friend is extremely distraught since he doesn't remember much of the night but I reassured him that any competent lawyer worth his degree will find it an easy case, especially with so much eyewitnesses at the scene with him. This however, is based off my knowledge of UK law. If any Irish law students, or lawyers can help me put his mind to rest a little bit while he searches for a legal representative it'll be much appreciated 🤞