Hello, How are you? Try one not away of your university and quite, exist some quites, and the price around the same of another places. Try a place not away of stop bus or the "metro". Any question send me msg I can help you.

Anna Chiado / baixa, is the worst place he can stay, can be very amazing and beautifull if you go as a tourist, but not if you live there. A lof of places bus just work at 22h / 23h of the night (so if you want go the party you need have a car what isn't good for find a place to the car or have places to put the car) you see a lot of people sleep in the street more than what you see during the day, it's a dangerous place in the night, etc. 

Like I said he should stay near of the college will be easy escape the traffic of the rush hour and when he want see the city know the places he can go in "metro" and in bus without any problem.

Hey!I think Lapa is a good place for you to stay:)

chiado baixa is very nice, but it could be expensive

there's many-many places to live near placa espanya and this is a good neighbourhood, if you want to travel around lisbon
just a tourist experience, locals would know better :)