I am currently on SSDI and will be 62 at the end of this year, my wife will be 61 in July, when can she apply and what percentage would she receive.
Your wife could be eligible for spousal benefits as early as age 62, or possibly even earlier if she has a child in her care who is eligible for benefits on your record (https://www.ssa.gov/planners/disability/dfamily2.html).
Unreduced spousal benefits are paid at a rate of 50% of the worker's primary insurance amount (PIA). Your primary insurance amount would be your full disability benefit rate. But, if your wife files for reduced spousal benefits at age 62, her benefit rate will be reduced by between 31% to 32%. Also, she will be deemed to file for her own retirement benefits when she applies for spousal benefits, and she will only be eligible for spousal benefits if 50% of your PIA is higher than her own full retirement age rate.
Another potential issue is the special disability family maximum, which can limit auxiliary (e.g. spousal, child) benefits payable on the record of a disabled worker (https://www.ssa.gov/OACT/COLA/dibfamilymax.html). This shouldn't be a problem in your case unless your disability benefit rate is less than around $1,200 per month.
Your wife may want to consider running the maximization software available on this website in order to explore her filing options.