Small business deal uncertainties

I'm under LOI for a small print media advertising company in my targeted Midwest region. The business has been fairly stable, but with modest declining revenue in recent years and a need to strengthen margins--the biggest growth lever will be through digital development. My background is in tech and digital transformation, so this is where I'd fit in strategically. The business is smaller than I'd like, but checks other important boxes (e.g. target region and service-based). There have been some emerging flags during diligence including: (1) Cash flow realities of this business make it too small for me to go 'all-in' from a personal income perspective, (2) Declining revenue and margins in recent 3 years (~3-5% per year decline) stated as tied to lack of digital capabilities, (3) Strong family ties to current operations, (4) Net take-home of this deal does not meet the owner's full needs for 'early retirement' as he wanted, so he's becoming more nervous. I'm considering either walking from this deal, or making an equity partner offer. As a partner, I could drive digitization of the business and ready it for a stronger exit in 5-8 years, keep the owner vested in the business while providing him needed income, and allow me to remain out of the day-to-day. I generally like the owner, find him trustworthy, honest, and we have complementary skills. Does anyone have experience with partial equity purchase of a small business? Is this generally a bad idea or not worth the effort? What makes an offer like this attractive to a seller?