OP, can he solve the problems if he thinks of them additively rather than multiplicatively?
For example on Ex. 2, where he's earning 3 dollars a week, have you tried leading him through it along the lines of 'ok, so how much would he earn in a week?' and assuming he gets that, saying 'ok, how about two weeks? if he earned 3 dollars the first week, and 3 dollars the second week, how much did he earn together?'
If he can solve them this way (obviously with single-digit numbers), I would bet that the multiplication way would start to make sense after a bit.
Also, how did he do on Lesson 49? Have you gone back to Lesson 49 and related it to this?