Will Jimmy fall off his platform?

Jelly, 6 bytes

n⁶Sċ2Ẓ

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Explanation:

n⁶Sċ2Ẓ  args: z (e.g. [['/', 'o', '\\'], [' ', '-']] => 0)
        implicit return value: z ([['/', 'o', '\\'], [' ', '-']])
n⁶      dyad-nilad pair ([[1, 1, 1], [0, 1]])
 ⁶       4th command-line argument or space [4th CLA assumed absent] (' ')
n        vectorized inequality ([[1, 1, 1], [0, 1]])
  S     reduction by addition with base case 0 ([1, 2, 1])
   ċ2   dyad-nilad pair (1)
    2    literal (2)
   ċ     number of occurrences of right in left (1)
     Ẓ  primality (0)

JavaScript (ES6), 38 bytes

Takes input as (a)(b). Returns \$0\$ or \$1\$.

a=>b=>b[a.search`o`]=='-'&/--/.test(b)

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How?

We look for the position of the middle part "o" of Jimmy's body in the first string and test wether there's a dash in the second string at the same position.

b[a.search`o`] == '-'

The only case where Jimmy would be unsafe in this situation is with a single-dash platform:

/o\
 -

So we additionally make sure that the platform has a width of at least \$2\$:

/--/.test(b)

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JavaScript (ES6), 36 bytes

Alternate version if we assume that there's always either dashes or spaces below Jimmy (i.e. the input is rectangular).

a=>b=>b[a.search`o`]!=0&/--/.test(b)

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Takes advantage of the fact that the coercion to a numeric value is \$0\$ for a space and NaN for a dash.

Excel, 67 45 44 bytes

=(MID(A2,FIND("o",A1),1)="-")*(TRIM(A2)>"-")

Put Jimmy in A1, on a platform in A2.

2 conditions checked:

• Is Jimmy's torso (o) on the platform?
• Is the platform more than just -?