When my now 25 year old daughter has invited guests (friends or a boyfriend), I appreciate it if they offer to help with dishes and just pick up after themselves, but would never in a million years assign chores. It would be polite of a long term guest to offer to help with something little like that- and many times I would expect the host would say no thank you to anything bigger than dishes, etc. I can imagine what a nice surprise it would be if I cam home from work and found the living room or bathroom cleaned up (maybe as a team effort by daughter and friend) as a gesture of appreciation, but absolutely not expected. (In my house, that never happened, btw.)

So I think the bf's parents are a little out of line.