It's just me and one other person on the mortgage.  3 other people and myself are on the title (joint tenancy). 

He wants me to a joint venture which means he will fund the project 100% and do a 60/40 split if i get it done in 4 months.

Maybe start small with a 4-plex and work your way up.There's a short-cut but only if you are well capitalized, and that is - to joint venture with experienced apartment investors in your local market.Hope that helps.

For example joint tenancy would entitle your mother to inherit the remaining share (this is generally how spouses hold title)  if it is tenants in common you may need to go through probate (this is how business partners generally hold title)

Well I made a mistake of joint venturing with someone back in 2017 on four properties.

It makes you jointly and severally liable as a property owner.

Since all of the marriage joint is sealed by drywall, it is no way for the home appraisal to determine.

It’s pretty bad if you can’t keep a fast food joint open.

You may also want to only joint venture on a flip (because it's short-term) or a large multi-family that would make the cash flow worth it. 

You're right though, we do definitely have some joint goals.