Speaking to a girl's father with regards to nikaah

My friend wants to marry. His mother is a Muslim but not religious and not practising (does not cover herself properly, no 5-time prayer, etc) and even has a boyfriend (she was divorced a while ago). My friend asked me how to approach a girl in university? Obviously, the proper way is through the parents, elders or imams, etc. Actually, I personally also need guidance on this matter. He says "since my mum is not religious, I cannot really approach the girl to speak and deliver my proposal as mum is not interested and would not be really helpful in this matter since she herself is involved in a haram relationship..."

Please, advise us on this topic. How to approach a girl whom you would like to propose? For example, if the girl is with several female friends at university, and they are near but do not hear the conversation between us, is this allowed? Or write something on a paper and give it to her in the presence of her friends (without writing any contact info except phone number just to hear her response, or write in the letter to give it back if she only sees him with friends, just letting her know about the intention to meet with her in front of her mahrams?) How can my friend eventually "catch" a girl at university in this case? I guess parents/elders/imaam will not go to university for this?