How much equity each founder gets in a startups has to be decided after serious deliberations on a number of factors. This is especially true when two or more friends (and worse, relatives) are coming together to start a venture.
Whatever the split, assuming that equity should be split equally between all founders is an incorrect starting point.
Each team will have their own dynamics, and emotional as well as rational reasons to decide the split of equity between them. I would urge them to consider the following factors:
- Importance of the person’s function to the team (e.g. technology, marketing, etc.)
- Criticality of that person being in the team
- Is he/she the only person with that skill set in the team
- The seniority of that person in professional life
- What is the person giving up to come to this venture (opportunity cost)
Here’s a link to a neat tool to help you decide on the equity split Co-Founder Equity Calculator