SJ's can be messy, too, by the way. and SP's are capable of being control freaks. not everything about type is set in stone. a lot has to do with upbringing, maturity/growing, learning from our own mistakes, etc.

i will agree, it does seem unlike an ISFP to become a teacher in his father's footsteps simply because he felt he had no other choice... but really just break it down into Si and Se. toss cleanliness factors aside. how is he with keeping up with bills, or money management in general? or time management? can he be a bit impulsive? childish? does he experience the world through his five senses or through an innate sense of what needs to be done?

moving on. i say, communication, communication, communication. and that's not always easy for ISFP's. i had an INFP exboyfriend, however, that broke that wall with me. if you can lay down an atmosphere that he can feel comfortable in, he'll be able to open up his problems more and more. a concerned, but non aggressive tone and honesty of your own feelings should help.