Student Loan solution or not

Learn22

£30k Student Loan - 
I plan to clear my son's Loan from my ISA. He will repay me @ £150 for 15 years. I will add £150 extra to my pension @ 40% tax relief. He avoids 6% APR on his loan. I lose approx 6% increase iny ISA growth but get 5 years of tax relief @ 40% then 10 years tax free income from him = £150 /month. I sleep better for next 15 years. How do I convince my wife it's a good idea!?
He will have a salary where he has to repay the £30k. He will prioritise saving a deposit for a flat.

Nasqueron

It's not a good deal financially for you, it is a good deal for him. 

You're ignoring inflation on your £150 a month so you're losing money in real terms and losing compound interest in your calculations though putting in pension for tax relief is ok. Student loans are almost never a good idea to repay though and what if your son cannot pay back £150 a month for some reason e.g. buying a house he has to declare the debt which affects affordability or if he loses his job.

Learn22

Many thanks for. reply.
I increase his repayment annually by 3%.
Less than say, 6% rate for Govt. loan.
I can do an excel calc when he starts earning next month and I have a payslip to look at.
He will be NHS employee, so should keep earning.