Undergrad degrees are not all that great. There will be many u will compete against and if economy is down, u will be forced to return to SG and earn less after a huge investment.
And Management and Econ are generic degrees.

U can do undergrad at SMU. And keep that 85k for grad degree or MBA after 4-5 years. It will ensure a grad degree from abroad and with job ex , u may be able to work abroad. People here are overstating the importance of Undergrad. U will need luck, good economy and chances to land a good deal.

If u are good, u can go to a good Grad Program later with this money. U are lucky that ur dad has this money. Use it wisely.