@Maureen F.- there is some great advice here about what to do and not to do - the IRA info was definitely great.
Adding to the other comments, I would not recommend your son attempt anything other than painting if he has no experience with it.
What seems like a simple project can quickly get out of hand or you won't get the same polished look compared to someone who does this for a living. Plus it will take forever if there's a laundry list.
I'm semi-skilled and having two jobs last year while trying to fix up my fiance's two family proved to be a major stress. Yes, we saved thousands on contractors, but at what cost?
I only did things like drywall repair/replacement, door repair, new bathroom floors, toilets, bath fans, vanities, some basement work, sidewalk repair, etc. It added up... paying a little extra for a turnkey property could be the way to go.
The second bit of advice for sourcing leads would be to drive around the more desirable neighborhoods in Dorchester based on your opinion and target some homes, maybe 25-50.
Have him hand write letters explaining his situation about wanting to buy a home, live in it for a long time, keep the house's character but losing out to investors/developers right now.
My friend did this when he was looking for a home and his response rate (after sending 2-3 letters per house) was over 50%. He was looking in one very specific part of Dorchester, and at the time nobody was in the market to sell, but that's your key to getting out of the MLS mess.
Dealing with a wholesaler will likely mean quick turnaround, limited inspection (or no inspection), and "cash" offer - aka no financing contingency. Too many risks.
Also, call around various banks (the local ones) and see what programs they offer where you can avoid PMI. Someone I met recently said he found a lender who would do 5% down and no PMI and I know someone who got a 15% down loan with no PMI.
Keep looking on the MLS, but have him try to source off-market leads with a personal, hand-written message. Best of luck in the hunt!