Thank you all, that explains it nicely. I will advise the parents.
In terms of accommodation they would be happy with nice hotel or short stay apt that is within a 5 min walk to the T then about 10 min from downtown. They are used to staying in pensions in Europe so being a little out of town is ok so long as public transport is easily accessible. They don’t need turndown service nor a daily maid service. Obviously being in an interesting neighbourhood is also a plus which makes me think that around Harvard or Cambridge might be an option…….
Anyway, thanks again for your assistance.