This ish what TS should do la 
(Provided TS salary can hit the max loan amount)
Old 4rm HDB (parent) = 250k need go back into CPF
New 4rm BTO (parent) = 350k (include levy)
TS buy Old 4rm (parent) = market value 450k (To wipe out TS CPF le then loan remaining from HDB/bank)
Parents received 450k from TS via TS HDB/Bank loan, 350k goes into BTO, parent have cash 100k in bank, use 20k renovation left 80k for buy bitcoins and buy one vietnamese wife for TS.
TS nao own the old 4rm and finance using CPF. Rent extra 2 rooms out to tiongbus and vietneses zeh zeh.
oh wait. if TS can afford 450k market value HDB. Wai not buy his own HDB!!?!!!?
ok la. because his parents BTO HDB 350k if next time sell away ish can earn la after MOP provided they no more buy le then ish 99 years