While it is not certain what type of immunity having been infected by any particular virus grants, if one is infected and survives they are in a better position than never having got it. In an odd twist of fate, during the 1918 pandemic older adults were the least vulnerable cohort, the hypothesis being that a related flu circulating in 1902 had built up antibodies in them. The pandemic ended with people either being dead or immune from having already been infected.
When the measles vaccination began no one over 15 was vaccinated, the reason being that measles was so virulent (ten times that of the flu) that virtually everyone over 15 had caught it and been immunized. The vaccinations were started in the 60s and it was soon discovered that a second vaccination had to occur while young. More recently there have been incidences of adults getting measles, even if they had been vaccinated, and some in the medical community recommend getting vaccinated once as an adult. Yet there virtually is no data as of now to know if an older person remains immune to measles even if vaccinated twice, because the vaccinated are not old enough. We will discover that over the next decade, but meanwhile us infected Baby Boomers can be thanked for our contribution to herd immunity for measles.
I don't want to cause alarm, I suspect twice vaccination will work at any age, but it's clinically proven that there are not as many antibodies built up from vaccination as from having been infected. Even if COVID-19 can be caught twice, it's likely not to be as bad with subsequent infections, for the same reason why people who catch colds a couple times a year usually are not floored by them. Some people may even catch colds without realizing, just as in the asymptomatic cases of COVID-19.
What all this means is that, yes, for Dolson and her family having been infected and survived is good news, even if it's possible to catch again, but they still need to isolate for the sake of others. It also means that while both previously infected and vaccinated people should be OK moving forward, the probabilities favor the previously infected having a little greater protection. I am in social isolation, but if I could perfectly control my fate I would get infected now while I was confident of my immune system, then quarantine myself from people for the duration of the pandemic.