Considering a $15k private investment in a small phone parts/repair wholesaler

Local parts wholesaler (rtfixes) reached out to me on Facebook. I’m considering putting in $15,000 (money I can afford to lose) but I want a sanity check before doing anything retarded

This wouldn’t be public stock, so I understand the risk and lack of liquidity are much higher (I’m not expecting guaranteed returns or anything unrealistic)

I really wanna do it bc I’m in the repair business and having someplace cheaper than MobileSentrix to buy from sounds awesome, and if I can help them do it, it could rly help long term