Whilst it may look rosy, possibly it is, check very carefully the amount of debt the business is owing.
Unless things are radically different in your country, once you sign on the dotted line as a partner, you will own half of the debt the business has.
Nothing is for free!
I run my own business, not in photography, over the decades I have seen some interesting partnerships thrive and others fail. Almost always, the businesses that fail, do so, because of debt.
Other times, not so often though, businesses fail due to a problem with one half of the partnership having difficulty, often a marital situation going sour, or ill health. These are not always avoidable, but things to be aware of.
I have been in two business partnerships, neither of them lasted the distance. One due to a marital breakup by the other party, the other due to the other partner being unable to live on the reduced income once the business profit was being shared by the other partner that came in, which was myself.
My first impression is to proceed very cautiously and really do due diligence, especially about outstanding debt and any ongoing debt. Car payments are a classic example of ongoing debt, these debts can lead to difficulty in a company that is struggling to keep payments one step ahead of the bankers.
Remember too, that at the moment, things around the world are tightening up enormously, big time. It is very possible that we are heading into a world depression, not nice, but certainly a plausible outcome.
If you feel it will be a nice fit with your current way of doing things, and, you don't have to change too much, it could be a good thing.
If you wish to grow and diversify your photographic work, it could be a good thing.
There will always be good and bad things, the idea is to pick something where the good things outweigh the bad things by a reasonable margin.
I looked at your gallery, interesting range of pictures, there is some creativity there. It is possible that the increased workload, may restrict your creative endeavours somewhat.
I decided many years ago to get out of photography, as a living. The only way to make reasonable money, meant my creative urges had to be suppressed to put food on the table. I have been extremely happy with my decision, you will possibly have to make that decision yourself, although I believe you are aware of this anyway.
Mick.