He was defeated on leaving in October.

He hasn't created a border in the Irish Sea

He didn't trigger Article 50.

I am not an expert but I believe checks won't be needed between NI and GB beyond those pre discussed and agreed with DUP etc regarding agriculture. There will be a bit more paperwork but AFAIK no extra checks.

Parliament already gave the Withdrawal Agreement a second reading but have made it clear they
dont want to pass it unamended and will kill it with wrecking amendments.