I'm no financial expert but "¥15.7tn ($143bn) of interest-bearing debt" is a lot of money, in case shit will end up hitting the proverbial fan (meaning a recession that will make refinancing a lot harder) then I don't see an easy way out for them. I also don't know what "¥27tn of total liabilities" really stands for, but that doesn't sound good either.
Adding those two numbers up gives you about $300 billion that is owed by SoftBank in one way or another (debt + liabilities), that is a lot of money that cannot easily be covered by SoftBank's current assets in case they'll become hungry for liquidity. And I don't think the biggest part of that sum has a long maturity (think 10, 20 even 30 years), probably most of it it's due in the next few years (even though I may be wrong on this one, I admit).