Hopefully Meghan's Dad can at least make the trip, even should he not be able to withstand walking her down the aisle. I see no problem really with Meghan's Mom walking her down the aisle if her father cannot. Plus Meghan's Mom has a younger half-brother (son of Doria's father Alvin Ragland and his second wife, Ava Burrow). This uncle of Meghan's (Alvin Joffrey Ragland) is two years younger than her. And reportedly, he is close to Meghan and her Mom. So he may be at the wedding. As a male relative (and the younger son of Meghan's maternal grandfather), Alvin Joffrey could also walk Meghan down the aisle if her father cannot.
In the below DF article updated in October 2017, there's a picture of Alvin Joffrey with his mother, Ava -- scroll all the way down
DailyMailTV reveals Meghan Markle's family roots | Daily Mail Online
Another photo of Alvin Joffrey Ragland:
https://www.linkedin.com/in/randomragland
Of course, there's also Markus Anderson of Soho House, who is like an older brother to Meghan. He could just as easily walk her down the aisle too, if her father cannot. Meghan's other maternal uncle, Joseph Johnson Jr., who sold family pictures to the media, is unlikely to be invited.
Meghan is also close to her niece, Ashleigh Hale, who is an attorney.
https://www.express.co.uk/news/roya...riend-Meghan-Markle-inspired-niece-Suits-role
Ashleigh's mother is Samantha Markle, but thankfully, Ashleigh and her brother, Christopher, were raised by their father's parents. So there are quite a few extended relatives in Meghan's family, including her mother's sister, Saundra, and her offspring. It's not clear if Meghan is close to her Aunt Saundra. Then there's Tom Markle, Sr.'s brother Fred (Father Dismas) who runs a religious congregation in Florida. He seems just as reclusive as Meghan's father.