hoh2

A friend visiting me from China. He is on B1, because it is his business trip, but on
his visa it says B1/B2. He planed to stay in US for 5 months, but when he entered US,
he had no return ticket back to China, and the officer said the business can be done
with 2 weeks, so he got a B1 stamp with 1 month to stay in US. Because he is already
afraid, and he did not know a 6 month long visa can only give him 1 month stay, so he
entered US with B1 stamp good only for 1 month.

Here are options are him: 1 extend the stay with B2 status, but he is here on B1,
will that be a change of status or extension? also, i heard this must be done within
30 days of status expiration date, but he only got 30 days totally in US, so how
could that be done?

2 leave usa for canada then come back. will the officer refuse him to enter,
becaues he left then came back the same day? will the offier simply say he already
got 30 days in usa and refuse to give him a new stamp even his visa still has 3
months to go?