If you legitimately invest the money in your dad's company, you would list still need to include it as an asset. However, shares of small, privately-held companies are notoriously hard to value. These investments typically decline in value from the initial investment amount since sale of the shares is limited. Thus, your $10k cash might be worth only$6-8k as this investment.
However, if your "investment" means loaning dad $10k for four years to get the money out of your account, then you must list the loan as an asset at face value (plus accrued interest).