If he is good for Indonesia, it will be good for Singapore. There are so many factors and forces in the vast country, not one single person will make any big changes. In the foreseeable short term, things look pretty settled in Indon, and business will proceed. He is not an extremist, nor has a history of siding with any particular group, so there is confidence in the country's stability. I think foreign investments are growing in Indon, whilst at home, Indonesia has enough resources to feed the world. Singapore will benefit from growth and prosperity in Indon. The rich and able Indonesians love Singapore. Once I was told by a rich Indonesian lady there that she loves being in Singapore because she can safely wear her jewelry in public in Singapore! Hopefully the remote areas of Indonesia does not see political factioning and separatist desires sprout, there will always be potential in imporverished and areas faraway from Jakarta's influence and control.
That's my own opinion of that country and Jokowi.
Cheers!