Provided you know something about aircraft ownership in the first place. Buying a plane isn't like buying a car.
I would really recommend joining a club to get any idea about what is involved in owning a plane. It would also give you an opportunity to meet some people who might be interested in being partners on a plane with you.
I agree. He could also buy into an existing partnership.
The thing I've seen a number of times to watch out for in partnership is to be 100% sure that the existing partners really intend to share on an equal basis.
I've twice run into the case where a couple of guys want someone to pay for an overhaul, but they don't really want to share the airplane equally. For example, I looked at Mooney where they were selling a third share, but one of the 'shares' was 'co-owned' by a father and son, who each would have equal access to the airplane as me. So they wanted me to pay 1/3 of the value of the partnership, but only get 1/4 of the use of the airplane.
I have a couple of friends in another partnership who are happy, but their arrangement seems crazy to me. The partners pay for their own gas, and they split the hangar and insurance every month. But they charge themselves zero dollars per hour for maintenace. Whenever anything breaks they expect each partner to chip in 1/3 of the cost.
In an extreme case, if one of them flies 2000 hours in one year then that partner will have the full use of an engine, but only have to pay 1/3 of the cost. They are happy with it, but I wouldn't be. YMMV.