Is there an alternative to soldering to connect boards?
Yes, there are ways. There is a system called "Press Fit" where the pins have a bulge in one end of them. This grips the inside of the holes in place of soldering.

A number of companies make them, such as TE Connectivity and Positronic.

Of course, these depend on the holes being just the right size, and finding the right connectors could be tricky... so... your mileage may vary.

But nothing is better than getting someone to solder the pins for you. You could teach one of your younger relatives to solder, for example...