The Dublin toddler was diagnosed with the severe neurological condition, which prevents him from walking outside without an aid and will eventually paralyse him from the waist down, when he was just 18 months old.
His mum, Lynn Keenan (29), works as a carer for children with disabilities and she quickly realised that Jacob (3) would need physiotherapy.
"When Jacob was born, we weren't aware that anything was wrong, except that he was resuscitated at birth," doting granny Mary Keenan (54) told the Herald.
"But Lynn had a feeling that something was wrong, she was very tuned in and she insisted on taking him to see a specialist.
"The diagnosis only confirmed what she had guessed and she just took it in her stride because she knew, from experience, that it could have been a lot worse.
"Luckily, she took Jacob to a baby swimming class when he was just 10 weeks old and he does it every year so it has helped him a lot, he's got great strength in his upper body and he's able to move around outside in a walker," the Tallaght native added.
Jacob's condition affects him from the waist down and his family have discovered that St Louis Children's Hospital in Missouri, has developed a procedure that is very successful.
"This procedure has had very positive results and we're very optimistic, we found out about it from Adam Curran's family," Mary explained.
"Adam's from Bray, he's had the operation already.
"The two of them are great little buddies, they support each other and it's lovely to see the other side of it, to see step by step how he's improved with the operation."
The Keenans hope to raise around €70,000 for the operation, which is called Selective Dorsal Rhizotomy - €50,000 for the operation and around €20,000 for follow-up treatment in the US.
The operation involves a neurosurgeon removing two of Jacob's vertebrae and looking at the nerve endings on his spinal cord to find out which are sending the wrong signals.
These nerve endings are then cut to ensure that little Jacob only gets the signal to walk.
Jacob's family have pledged to give any money that does not go towards Jacob's treatment and transport to the States to Enable Ireland, a charity which helps children with the same condition.
Donations can be sent to Jacobs Journey, AIB Tallaght, Sort Code 93-33-17, Account Number 56430036.